VOLUME 70, NUMBER 4, 2016 GEOMATICA

THE JOURNAL OF GEOSPATIAL INFORMATION SCIENCE, TECHNOLOGY AND PRACTICE LA REVUE DES SCIENCES DE L’INFORMATION GÉOSPATIALE, DE LA TECHNOLOGIE ET DE LA PRATIQUE For personal use only. Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17

VOLUME 70, NUMÉRO 4, 2016 1 Vol. 70 2016 No. 4 GEOMATICA THE JOURNAL OF GEOSPATIAL INFORMATION SCIENCE, TECHNOLOGY AND PRACTICE / LA REVUE DES SCIENCES DE L’INFORMATION GÉOSPATIALE, DE LA TECHNOLOGIE ET DE LA PRATIQUE

FEATURES / ARTICLES DE FOND

269 mR-V: Line Simplification through Mnemonic Rasterization Emmanuel Stefanakis

283 DEM Fusion of Elevation REST API Data in Support of Rapid Flood Modelling H. McGrath, E. Stefanakis, M. Nastev

ARTICLES / ARTICLES City of Williams Lake, B.C. (see/voir page 322).

298 Movements of the ’s Suspended Span Measured by GNSS Technology...... DEPARTMENTS / CHRONIQUES Rock Santerre, Youssef Smadi, ...... 263 President’s Report / Rapport du président Stéphanie Bourgon Rodolphe Devillers 313 Initialization and Occupation Time for Kinematic 265 From the Editor / Note du rédacteur en chef Surveys using Online Precise Point Positioning Izaak de Rijcke C. Gil Mendoza, M. Berber For personal use only. 319 Geomatics and the Law / The Interaction of Law and Geography in the Williams Lake 317 Harry D.G. Currie, OLS—an Appreciation Indian Band Specific Claim David H. Gray Roger Townshend and Bert Groenenberg 325 Book Review...... ANNOUNCEMENTS / ANNONCES Izaak de Rijcke 327 Fifty Years Ago...... IFC/CAI Life Members Night / Soirée des membres à vie / William R. (Bill) Brookes 2017 CCA Conference / One Day Workshop 330 CIG Executive and Councillors 2016–2017 / Membres 267 CIG Certification Program / Programme de exécutifs ßet conseillers de l’ACSG 2016–2017

Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17 certification pour les spécialistes en géomatique 337 Association of Lands Surveyors / 268 Call for Papers: Geomatica 2017 Association des arpenteurs des terres du Canada 318 GeoAlliance Canada 2017 Board of Directors Jean-Claude Tétreault 326 Geomatica Award / Prix Geomatica 339 CIG Sustaining Members / Membres de soutien de l’ACSG 336 Geomatica Volume 71, 2017, Online Subscription 342 Welcome New CIG Members / Bienvenue aux 340 New CIG Sustaining Member / Nouveau membre de nouveaux membres de l’ACSG 2016 soutien de l’ACSG : RME Geomatics 344 Membership List 2016 / Liste des membres 2016 341 New CIG Sustaining Member / Nouveau membre de

soutien de l’ACSG : GÉOLOCATION 348 5Index to/du Volume 70, 2016 343 FIG Working Week 2017 / ISPRS Geospatial Week 2017 350 Calendar of Events / Calendrier des événements

Vol. 70, No. 4, 2016 GEOMATICA 261 ISSN (electronic / électronique): 1925-4296 ISSN (print / imprimé): 1195-1036 ADVERTISING / GEOMATICA PUBLICITÉ Published by / Publié par

Esri Canada ...... outside back cover/ Canadian Institute of Geomatics / couverture arrière extérieure L'Association canadienne des sciences géomatiques GeoEd Canada ...... 329 Alex Giannelia President / Président

Editorial Staff / Équipe de rédaction Izaak de Rijcke Editor / Rédacteur en chef COVER / COUVERTURE Laura Duke Production and Advertising / Production et publicité Christine Parent French Copy Editor / Rédactrice-réviseure français The , stretching across the St. Lawrence River west of , is the Amy Barker, William R. (Bill) Brookes, Jean MacGillivray, world’s longest span cantilever bridge at 548.6 Alice Meilleur, Mike Pinch Assistant Editors / Réviseurs metres between the main piers. Construction on William R. (Bill) Brookes / Jean-Noël Lechasseur the Quebec Bridge was completed 100 years ago Departments’ Editors / Rédacteurs des chroniques in 1917, following two tragic failures—in 1907 and 1916—and the loss of 89 lives. The Diane Cole Design Consultant / Consultante en conception impres sive road, rail and pedestrian bridge was largely designed and built by Canadian engineers Associate Editors / Rédacteurs techniques using an innovative K-truss design and was the first bridge in North America to use nickel steel as Claude Caron Business Geomatics / Géomatique d’affaires a structural material. Universally recognized as a Jean Gagnon Cadastral Surveys / Levés fonciers symbol of engineering excellence, the Canadian Adam Chrzanowski Engineering and Mining Surveys / Levés miniers et d'ingénierie (now the Engineering Institute of Canada) and American Society of Civil Engineers declared the Georgia Fotopoulos Geodesy and Control Surveys / Géodésie et levés de contrôle Quebec Bridge a historic monument in 1987, and, on Songnian Li Geographic Information Systems and Cartography / January 24, 1996, the bridge was declared a National Historic Site of Canada. Systèmes d'information géographique et cartographie Izaak de Rijcke Geomatics and the Law / La géomatique et le droit The Quebec Bridge is the subject of a paper entitled: "Movements of the Quebec Bridge’s suspended Robert van Wyngaarden Management of Geomatics / Gestion de la géomatique span measured by GNSS technology," published in Rodolphe Devillers Marine Geomatics / Géomatique marine this Geomatica issue (see p. 298). For personal use only. Suzana Dragićević Modelling and Decision Support / Modélisation et aide à la décision Photographic credit : R. Santerre, CRG, Laval Stéphane Roche Participatory GIS / SIG participatifs University, Quebec City Ayman Habib and / et Costas Armenakis Photogrammetry / Photogrammétrie Ahmed El-Rabanny Satellite Positioning and Navigation / Positionnement et navigation par satellite Le pont de Québec, qui enjambe le fleuve Saint-Laurent à l’ouest de la ville de Québec, est le pont Gordon Plunkett Spatial Data Infrastructure / Infrastructure de données spatiales can tilever ayant la plus longue portée libre au Jonathan Li Remote Sensing and Digital Mapping / Télédétection et cartographie numérique monde, avec 548,6 mètres entre ses deux princi- paux piliers. La construction du pont de Québec a Saeid Homayouni Remote Sensing and GIS / Télédétection et SIG été complétée il y a 100 ans, en 1917, après deux échecs tragiques— en 1907 et en 1916—causant la Publication Committee / Comité des publications mort de 89 personnes. Cet impressionnant pont routier, ferroviaire et pié tonnier a été largement Izaak de Rijcke, Amy Barker, William (Bill) Brookes, Laura Duke, conçu et construit par des ingénieurs canadiens Jean MacGillivray, Mike Pinch qui ont utilisé un concept inno vateur de système

Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17 Geomatica is published four times a year in the interest of professionals working in the geomatics sciences, by the de poutres en K et il était le premier pont en Canadian Institute of Geomatics, 900 Dynes Road, Suite 100 D, Ottawa, Ontario K2C 3L6, Canada. Telephone: (613) Amérique du Nord à utiliser l’acier au nickel 224-9851, Fax: (613) 224-9577, E-mail: [email protected], Website: http://www.cig-acsg.ca. Subscription rate for non-members is $290 Canadian per year + 13% HST in Canada (# R122381403). Membership dues include subscrip- comme matériau structural. Universellement tion to Geomatica. Subscription price of $25.00 is part of membership benefits and cannot be deducted from dues. reconnu comme symbole d’excel lence en Copyright of all text material from Geomatica belongs to the Institute. Abstracts and brief quotations may be made if reference is credited to Geomatica. Large text abstracts may not be reproduced without permission. CIG cannot ingénierie, l’Institut canadien des ingénieurs et accept responsibility for the accuracy of information supplied herein or for any opinion expressed. l’American Society of Civil Engineers ont classé La revue Geomatica est publiée quatre fois par année à l'intention des professionnels qui oeuvrent dans le domaine le pont de Québec comme monument his torique des sciences géomatiques par l'Association canadienne des sciences géomatiques, 900, rue Dynes, bureau 100 D, en 1987 et, le 24 janvier 1996, le pont a été Ottawa, Ontario K2C 3L6, Canada. Téléphone : (613) 224-9851, télécopieur : (613) 224-9577, courrier électronique : [email protected], site Web : http://www.cig-acsg.ca. Le tarif d'abonnement pour les non membres est de 290 $ désigné lieu historique national du Canada. canadiens par année plus la TVH de 13 % au Canada (No. R122381403). Les droits d'inscription comprennent l'abon- nement à Geomatica. Le tarif d'abonnement à la revue (25,00 $) fait partie des avantages aux membres et ne peut Le pont de Québec fait l’objet d’un article (en être déduit de la cotisation. anglais) publié dans ce numéro de Geomatica Tous droits réservés à l'Association canadienne des sciences géomatiques en ce qui a trait aux articles publiés dans Geomatica. Les résumés et citations peuvent être utilisés en mentionnant la source. La reproduction des articles est por tant sur les mouvements de la travée centrale interdite sans autorisation. L'ACSG se désiste de toute responsabilité de l'exactitude des renseignements fournis du pont de Québec mesurés avec la technologie dans cette publication et de toute opinion exprimée dans les présentes. GNSS (voir p. 298). Authorized as publications mail by the Post Office Department, Ottawa, and for payment of postage in cash. Agreement #40007094. December 2016. Crédit photographique : R. Santerre, CRG, Autorisé comme envoi de publications par la Société canadienne des postes, Ottawa, et pour paiement des frais de Université Laval, Québec poste en espèces. Numéro de la convention 40007094. Décembre 2016.

262 GEOMATICA Vol. 70, No. 4, 2016 MOVEMENTS OF THE QUEBEC BRIDGE’S SUSPENDED SPAN MEASURED BY GNSS TECHNOLOGY

Rock Santerre, Youssef Smadi and Stéphanie Bourgon Université Laval, Québec (Canada)

The Quebec Bridge was completed in 1917 and it is still the longest cantilever bridge in the world. Overall, the actual movements of its suspended span, as detected by GNSS (between 2012 and 2013), are in fair agreement with the original design calculations: for the train loading effect on the vertical movement (17 cm for one freight train); the transversal wind load effect on the transversal movement (32 cm for a wind speed of 170 km/h); and the temperature loading effect on the verti cal movement of the suspended span (3.2cm for a 50°C temperature variation). Further movements have been detected by GNSS technology, namely: the transversal and longitudinal movements of the suspended bridge span due to train passages (11 cm transversally, at the top of the suspended span, and 1 cm longitudinally); the transversal movement of the bridge caused by solar radiation (differential) conditions on both sides of the bridge (5 cm for high solar radiation values); and the longitudinal movement of the suspended span of the Quebec Bridge at temperatures lower than 6°C (7 cm to −25°C).

La construction du pont de Québec a été achevée en 1917 et il est toujours le plus long pont cantilever au monde. Dans l'ensemble, les mouvements actuels de sa travée suspendue détectés par GNSS (entre 2012 et 2013) correspondent bien avec les calculs d'origine : pour l'effet de charge des trains sur le mouvement vertical (17 cm pour un train de fret); l'effet de charge du vent transversal sur le mouvement transversal (32 cm pour une vitesse de vent de 170 km/h); et l'effet de charge de la tem pérature sur le mouvement vertical de la travée suspendue (3,2cm pour une variation de température de 50°C). D'autres mouvements ont été détectés par la technologie GNSS, à savoir : les mouvements transversaux et longitudinaux de la travée suspendue du pont en raison du passage de trains (11 cm transversalement, au sommet de la travée suspendue et For personal use only. 1 cm lon gi tudinalement); le déplacement transversal du pont provoqué par les conditions du rayonnement solaire (différen tiel) sur les deux côtés du pont (5cm pour les valeurs élevées de rayonnement solaire); et le déplacement longitudinal de la travée suspendue à une température inférieure à 6°C (7 cm à −25°C).

Introduction the Quebec Bridge. Furthermore, in order This paper contains the analysis of to take into account the movement of the the 3D deformation of the Quebec The origin of this project was to installed radar, a GNSS antenna (Global Bridge’s suspended span as measured bet ter establish the actual clearance of Navigation Satellite Systems including by GNSS technology as functions of the Quebec Bridge, which crosses the the American GPS and the Russian train and wind loads, along with the St. Lawrence River near Quebec City, GLONASS systems) connected to a effects of temperature, including solar and to potentially increase the number GNSS receiver, was installed on top of radiation. The next sections present a Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17 of tall ships that can securely pass under the central suspended span of the bridge short description and the history of the the bridge and reach the Port of 34 m above the radar. Quebec Bridge and the equipment and Montreal. For this purpose, the Montreal Although the original goal of the data used to perform this analysis. Port Authority installed a radar instru- experiment was not dedicated to moni- ment under the structure of the Quebec toring the 3D deformation of the Bridge to monitor the St. Lawrence Quebec Bridge, we asked to have The Quebec Bridge River water level. This project was done access to the GNSS data collected on in collaboration with the Canadian top of the Quebec Bridge’s suspended The Quebec Bridge (46° 45’ N, 71° Coast Guard (CCG) and the Canadian span for analysis. This was an opportu- 17’ W) is the first bridge over the Hydrographic Service (CHS), with the ni ty to monitor one of the most famous St. Lawrence River encountered by agreement of the Canadian National engineering structures in Canada built ships travelling upstream from the Gulf (CN) Railway Company, the owner of a century ago. of St. Lawrence and the Atlantic Ocean.

298 GEOMATICA dx.doi.org/10.5623/cig2016-405 Vol. 70, No. 4, 2016 This bridge is located about 10 km The technical specifications of the interesting to note that the ends of the upstream from Quebec City and about bridge are given in Table 1, as extracted cantilever arms dropped by 19.4 cm 250 km downstream from Montreal in from the original documentation given (7 5/8 in) once the suspended span was Quebec, Canada. in the Imperial (British) units [DRC lifted. The first transit of a train over the As indicated on the actual chart of 1908a,b]. The metric equivalents are bridge occurred on October 17, 1917, CHS, the clearance of the Quebec Bridge also given in this table. Figure 1 dis- and it was officially inaugurated on with respect to the High Water, Large plays pictures of the Quebec cantilever August 22, 1919. Let us also remember Tide (HWLT) is 46 m. In Quebec City, bridge taken in summer and winter sea- that the southern part of the first Quebec the tide can reach up to 5–6 m depending sons. The GNSS antenna location, on Bridge, under construction, collapsed on the time of the year. In fact, there are top of the suspended span, is indicated on August 1907 because of a structural some ships that can pass under the by the red arrow. design problem. Quebec Bridge only when the tide is To give a short history, it is worth The Quebec Bridge is still the falling. This shows the importance of mentioning that the central suspended longest cantilever bridge in the world establishing the actual (and the predicted) span was successfully lifted and installed and it was the longest bridge (of all bridge clearance along with the tide on September 20, 1917 (the first attempt types) between 1917 and 1929. It was level measured by nearby tide gauges. failed on September 11, 1916). It is also recorded as a Canadian national historic site in 1996 by the Government of Table 1: Technical specifications of the Quebec Bridge. Canada and it was recognised as an international historic civil engineering Length, Width, Height Feet Metres landmark in 1987 by the American Length of suspended span 640 195.1 Society of Civil Engineers and the Length of cantilever arms 580 176.8 Canadian Society for Civil Engineering. Length of anchor arms 515 157.0 In 1917, the bridge had two railways and two sidewalks. A car lane was Total length of steel work 3 239 987.2 added between the two railways in Distance between main piers* 1 800 548.6 1929. Later on in 1948, one of the rail- Width (external) of the bridge 100 30.5 ways (to the downstream side) and one Height of main posts 310 94.5 of the sidewalks (to the upstream side) were removed, and the second railway Height of suspended span (at the center) 110 33.5 was slightly shifted (to the upstream Weight imperial metric side) in order to widen the car lane. tons tons Currently, three traffic lanes for For personal use only. Total weight of steel** superstructure 66 480 60 310 cars are present: two lanes in the north direction and one lane in the south Weight of the suspended span 5 510 4 999 direction in the morning, and vice versa * World record for a cantilever bridge; ** 75% carbon steel and 25% nickel steel in the evening. The central car lane is Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17

Figure 1: The Quebec Bridge, left—in summer from the south shore; right—in winter from the north shore.

Vol. 70, No. 4, 2016 GEOMATICA 299 Figure 2: Left—Location of the GNSS antenna on the top of the Quebec Bridge (in the background, the Pierre-Laporte suspension bridge with the anemometer location indicated with the circled arrow). Source of the pho to graph: Canadian Coast Guard. Right—The Miros radar installed under the suspended span of the Quebec Bridge. Source of the photograph: Canadian Hydrographic Service.

closed at noon and during nights and intervals. Altogether, almost 18 mil lion The reference station was weekends. Every week day (but less observation epochs were recorded and equipped with a multi-frequency GNSS often during the weekend), around processed for a total of 140 GB of GNSS Trimble NetR5 receiver and a geodetic 35 000 cars (500 cars per 15 minutes data (including the GNSS reference sta- Trimble Zephyr antenna. The GPS- during rush hours), 4 freight trains tion files) in the ASCII RINEX format. GLONASS ambiguity fixed ionos- (with about 30 wagons) and 8 passen- The distance between the Quebec pheric free (L1 and L2) solutions with a ger trains transit the bridge (there is no Bridge and the nearest permanent GNSS 10° elevation mask angles were passenger train service between 10 reference station (QBC2) was about produced using the Trimble Business p.m. and 5 a.m.). The maximum train 7 km with a height difference of about Center (TBC) post-processing software For personal use only. speed is regulated to 64 km/h and the 70 m. This might be a proper setup for [Trimble 2012]. maximum car speed is limited to the original objective of the project, Due to the large amount of GNSS 70 km/h. Since 1991, the transit of which was to measure (at an accuracy of data, the TBC software was used for large trucks has been forbidden. 0.1 m) the bridge clearance for safe ship several features: efficient data screen- Figure 2 (left) also depicts the view of navigation, but this is not optimal for ing, reliable ambiguity-fixing algo- the train , the three car lanes and bridge deformation monitoring because rithms, automated cycle-slip detec tion the sidewalk as seen from the GNSS of the long distance and large height dif- and correction engine, and its user- antenna location. ference between these two GNSS anten- friendly interface. The observation files nas. Even though it would have been in the RINEX format were processed preferable to have a closer GNSS refer- in the kinematic mode. Therefore a GNSS Equipment and ence station to mitigate GNSS errors new set of 3D coordinates was esti- (especially the tropospheric error which mated at every epoch. Altogether, it Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17 the Auxiliary Data mainly affects GNSS height determina- took 15 days to post-process this vol- tion), one can expect that for a short period ume of GNSS data (140 GB) on 10 A chokering (Antcom) antenna of time (such as a train passage of a few personal computers. All the results are (see Figure 2, left) connected to a multi- minutes) the tropospheric modelling reported in Smadi [2015]. frequency geodetic Ashtech (Proflex error will stay almost constant and will The instantaneously estimated 500) GNSS (GPS-GLONASS) receiver not significantly deteriorate the detection precision (epoch by epoch) of the hor- was installed on top of the central sus- of the vertical displacement of the GNSS izontal components at 95% probability pended span of the bridge on the antenna located on the top of the bridge’s level was typically 1.5–2.5 cm for the upstream side (the side of the railway). suspended span. Let’s also recall that horizontal and vertical components, The data set was available from the tropospheric delay mismodelling has respectively [Smadi 2015]. Let us keep beginning of July 2012 up to mid-July almost no effect on the horizontal GNSS in mind that the precision of the dis- 2013, with observations recorded at 1 s coordinates [Santerre 1991]. placement (the coordinate variation in

300 GEOMATICA Vol. 70, No. 4, 2016 time) is much better, especially for a the Quebec Bridge. Table 2 shows the downstream direction and the vertical short time duration where the GNSS summary of the auxiliary sensor values component has a positive value in the up errors are highly correlated. From the during the observation period. (zenith) direction. This transformation analysis of this large GNSS data set, a A Miros microwave radar remote was done using the known bearing of realistic precision of 5 and 8 mm for the sensor for the ocean surface radar, the longitudinal axis of the Quebec horizontal and vertical displacements, model SM-094, was used to measure the Bridge, which is 340°. respectively, can be stated. Moreover, clearance (instantaneous vertical distance To analyse the Quebec Bridge the moving average filtering helps to at 1 s intervals) between the bottom of the deformations, let us remember that the significantly reduce the noise associat ed suspended span of the Quebec Bridge and GPS system has been used for decades with the GNSS observations, as will be the water level of the St. Lawrence River for deformation monitoring of large shown in the next sections. (Figure 2, right). According to the manu- engineering structures such as Several auxiliary data sensors facturer, the accuracy of an individual [Hyzak et al. 1995; Xu et al. 2010]. were available, such as an ultrasonic measurement is 1 cm. As one will see Dams [DeLoach 1989], towers and anemometer (Young Model 81000), to later, the measurements not only contain buildings [Lovse et al. 1995; Yi et al. collect wind velocity in N-S, E-W and information about tides, but they are also 2012] are also monitored using GPS U-D directions, averaged every 10 min affected by waves. During the winter sea- (GNSS) technique. Some of the along with the air temperature. This son, the radar pulses bounce back from ice recently constructed mega structures anemometer is located on top of a light blocks that are floating on the river. Thus are permanently equipped with GPS pole just south of the north tower on the the radar data obtained in this season were (GNSS) receivers along with other upstream side of the Pierre-Laporte sus- not used for the analysis. sensors such as accelerometers, tilt pension bridge, which is located 200 m The variations in the coordinates of sensors and so on. GPS (GNSS) tech- upstream of the Quebec Bridge (see the antenna are with respect to the aver- nology is now part of structural health Figure 2, left). Unfortunately, no age 3D coordinate values obtained from monitoring toolboxes [USACE 2002; anemometer is installed over the a 24 h static solution for the day March 3, Santerre 2011]. Quebec Bridge. The solar radiation val- 2013. This day was selected because the ues were recorded by the MeteoLaval average air temperature value was close station located about 4 km from the to zero (0.7°C) and the wind velocity was Movement Analysis Quebec Bridge. The traffic loops operat- as low as 4 km/h in the transversal direc- ed by Quebec Department of tion. The results presented in the next Caused by Train and Transportation (MTQ) were used to sections are, in fact, the coordinate varia- provide the total number of cars for the tions (displacement) of the GNSS Car Load 15 min intervals. The arrival and depar- anten na (located on top center of the sus- For personal use only. ture times of passengers and freight pended span) expressed in the bridge Vertical and Transversal trains were provided by the CN Railway local reference frame (L, T, V), where the Displacements Company for the two nearby train sta- longitudinal (L) component has a positive tions, namely Ste-Foy and Charny, value toward the river’s north shore Figure 3 (top) shows typical respectively. These are located 1.5 km direction, the transversal (T) component effects of freight train transits on the north and 4 km south from the center of has a positive value toward the river’s vertical (V, green lines) and transversal (T, blue lines) components as detected Table 2: Summary of the auxiliary sensor values from July 2012 to mid-July 2013. by the GNSS receiver every second for a period of 6 min. Radar measure- Minimum Maximum Mean ments (vertical distances at every s) North car traffic flow (/15 min.) 0 509 118 are represented by dark lines and are intentionally shift ed by 5cm to avoid Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17 South car traffic flow (/15 min.) 0 503 103 masking the two other lines. In fact, Trains (/week) 45 71 61 the radar values are the measurement residuals after the main tidal con- Ambient air temperature (°C) –28 33 7.3 stituents have been removed (by the CHS). Remember that the tide height 2 Solar radiation (W/m ) 5 1397 299 can reach 5–6 m in Quebec City. The superimposed lines are the results of Longitudinal wind speed (km/h) –41 30 –2.4 applying a 10 s window moving aver- (positive from South) age filtering. This technique helps to Transversal wind speed (km/h) –71 98 3.4 significantly reduce the data noise, (positive from West) especially for the radar measurements affected by the roughness of the river

Vol. 70, No. 4, 2016 GEOMATICA 301 Figure 3: Vertical (V) and transversal (T) displacements during the transit of a freight train (top) and during the transit of a

For personal use only. passenger train (bottom).

water surface. There is indeed a good on the weight and the length of the train. live load consisting of 2 Cooper’s agreement between the radar measure- The duration of the transit probably Class E60 locomotives (60 000 ments and the vertical variation of the depends also on the speed of the train. pounds or 27 273 kg), followed by GNSS antenna coordinates. Unfortunately, no such information was 5000 pounds/linear foot (7456 kg/m) One can notice that the less noisy available from the CN train file provided on each track, should be 33.7 cm GNSS antenna coordinate variations to us. For the freight train transits, the (13.25 in). As mentioned before, there are related to the transversal compo- largest subsidence value reached 17 cm is currently only one railway track and nents and the vertical coordinate and the maximum transit duration was the bridge was originally designed with varia tions are noisier. This is because 3 min. The asymmetric shape of the two railway tracks.

Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17 GNSS (GPS) is less precise in the graphs is attributed to change in the train The transversal displacement of vertical direction [Santerre 1991] speed or different weights of wagons. This the antenna can be explained by a and that the bridge movements asymmetric shape happens more often for lever arm (tilt) effect. Remember that induced by car and train transits are freight trains going toward the north direc- the train track and the GNSS antenna mainly in the vertical direction. tion probably because they have to reduce were located on the upstream side of Transversal values were not always their speed to enter the curve travelling the bridge (not in the middle point of centered at zero because when the westward before approaching the near by the transversal section of the bridge, wind blows transversally, the sus- Ste-Foy train station. which is 31 m wide), and the GNSS pended span moves in the transversal The vertical variations of the GNSS antenna is about 34 m above the rail- direction. The effect of the wind load antenna were in fair agreement with the way. The ratio of the peak values is discussed later. calculated values [DRC 1908a,b], which between the transversal and the vertical The shape and the size of the state that the deflection at middle of displacement (T/V) is 0.66 ±0.08 (for detected movements certainly depend channel (suspended) span caused by a all types of freight or passenger train).

302 GEOMATICA Vol. 70, No. 4, 2016 The maximum value of the transversal about 1 min. For comparison, the weight amplitude or period values between displacement was about 11 cm. This by unit of length of a passenger wagon is the night period (with the lowest means that the train load seems also to less than 2500 kg/m vs about 6000 kg/m number of car transits) and the two produce a tilt effect on the suspended for a tank wagon. rush hours was noticed. span along with a sub si dence effect. The The vertical coordinate variations transversal movement correlates perfectly of the GNSS antenna caused by the car Longitudinal with the vertical displacement. In this load were not visually perceptible even Displacements con figuration, it is even easier to detect during traffic rush hours. In fact, the car train transit with the transversal GNSS load is considerably smaller than the The train load effect on the component because it has a greater train load (for comparison, the weight longi tudinal coordinate variation of pre ci sion than the vertical component. by unit of length of a car is less than the antenna (located at the middle of Figure 3 (bottom) shows typical 400 kg/m ver sus about 6000kg/m for a the suspended span) was also investi- effect of passenger train transits. The tank wagon). To confirm the visual gated. Figure 4 presents graphs where passenger trains, which are typically inspection, FFT analysis was performed longitudinal displacement of the smaller and travel at higher speed than during the night (0:00–1:15 a.m., with GNSS antenna (maximum value of freight trains, produce smaller peaks. an average of 300 passing cars), during 1 cm) due to freight trains has been The maximum measured vertical sub- the morning rush hour (6:45–8:00 a.m., noted. The longitudinal coordinate sidence value was about 2.5 cm, while with up to 6000 passing cars) and variations are in magenta and the the mini mum subsidence was as low during the evening rush hour (4:00–5:15 transversal variation is in blue. The as 1.0 cm. The longest duration of the p.m. with up to 6000 passing cars). In lat ter wassuperimposed to clear ly load effect of the passenger trains was fact, no significant difference in FFT identify the train transits. In fact, the For personal use only. Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17

Figure 4: Longitudinal (L) and transversal (T) displacements during freight train transits.

Vol. 70, No. 4, 2016 GEOMATICA 303 longitudinal coordinate variation was response model to explain this of values for the cal culation of the detected for 45% of the freight train phenom e non. However, this model daily cross correlation value (also transits and for only 10% of the would have to be adapted for a structure reported on the lower left of each pas senger train transits. such as the cantilever Quebec Bridge. graph in Figure 5), only the days that The slope of the longitudinal had at least 25% of common epochs vari ation at the time corresponding to between GNSS and wind data values the transversal peak value is positive Movement Analysis were retained. Altogether, 54 days (displacement in northward direction) meet these criteria and 12 days had for the northbound trains and negative Caused by Wind Load wind speed values larger than 60 km/h (displacement in southward direction) (the maximum value recorded was for the southbound trains. This rela- Transversal Displacements 98 km/h). To better distinguish the two tively small coordinate variation time series, two different origins for demonstrates the great capability of Figure 5 presents examples for six the vertical axes have been selected. GNSS results to monitor engineering windy days, showing the transversal The cross-correlation coefficients infrastructures. This behaviour might coordinate variations (blue line in cm) of range from 0.80 to 0.97, as indicated be explained by the kinetic energy the GNSS antenna atop the suspended in the lower left corner of the graphs. transferring from the train to the sus- span at 10 min intervals, filtered using a This indicates that the bridge reacts pended span. In fact, the suspended 10 min moving average and the aver- quite instantaneously to the transversal span is hinged on by the cantilever aged transversal wind speed as recorded wind load. The high correlation arms and the suspended span move- by the anemometer every 10 min (green between both time series is clearly vis- ment is also attenuated by shock line in km/h). In order to distinguish and ible from the graphs, especially when absorbers (traction brakes) installed study just the effect of the wind loading, the wind speed is high. The largest between the cantilever arms and the the days with high solar radiation (from reported winds were 98 km/h from the suspended span. 500 up to 1400 W/m2) were discarded west (day: 13-01-31) with a displace- Xia et al. [2000] reported train and the periods of train transits were ment of 10 cm in the eastward direc tion load effects on a suspension bridge as removed. The impact of solar radiation and almost 60 km/h from the east (day: measured by GPS receivers. They also will be dis cussed in the next sec tion. 13-01-20) with a displacement of 6 cm pre sented a suspension bridge dynamic Furthermore, to have a minimal number in the westward direction. The largest For personal use only. Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17

Figure 5: Transversal displacement of the central suspended span versus transversal wind speed for six different days.

304 GEOMATICA Vol. 70, No. 4, 2016 Table 3: Coefficients of the best-fit parabola and their precisions. a ±σa (m h2/km2) b ±σb (m h/km) c ±σc (m) R2 y(@170 km/h) (m)

East and west winds 0.000 007 3 0.000 82 -0.005 4 0.79 0.346 (7161 values) ±0.000 000 3 ±0.000 02 ±0.000 3

West wind only 0.000 008 2 0.000 49 –0.000 9 0.79 0.320 (2938 values) ±0.000 000 4 ±0.000 03 ±0.000 4

diurnal wind speed variation also (sampled every 10 min) was 7161. In this lated and a value of 34.6 cm was occurred in day 13-01-20; about graph, the transversal displacements obtained. The red parabo la was interpo- 130 km/h wind change for total associated with the east transversal wind lated from the 1908 prediction for a transversal displacement of 14cm (in green) have been changed of sign. transversal wind speed of 170 km/h during that day. It is worth mention- The blue dots are associated with the west (see below). The third parabola (in ing that the time of wind zero cross- winds. Altogether, there were 10 days brown) was obtained from the best fit ings (green line) coincides with the where the west wind blew above 60 km/h to the west wind speed only (for a total transversal dis placement zero cross ings (up to 98 km/h) and two days with maxi- of 2938 measurements). The R2 value (blue line). mum east wind at 60 km/h. The best fit of 0.79, associated with the parabola To see the complete behavior of parabola (in magenta) has been estimated fits, successfully passed the Fisher test. the transversal wind effect on the by least-square and their coefficients and It can be seen in Figure 6 that the trans versal coordinate variation, all the their precisions are reported in Table 3. transversal effect of the wind from data sets have been displayed together Using the parabola coefficient, the value the east direction (green dots) seems in Figure 6. The total number of values for a 170 km/h wind speed was extrapo- to be greater than the east wind (blue For personal use only. Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17

Figure 6: Distributions of the transversal displacement of the central suspended span as a function of the transversal wind speed.

Vol. 70, No. 4, 2016 GEOMATICA 305 dots). This suggests that the west (equal to 47 m/s) using the fol lowing transversal displacement of 20 cm for speed measured by the anemometer equation and the appropriate unit a wind speed of up to 20 m/s ρ 2 located on the Pierre-Laporte bridge con ver sion: P = ½ air V , where P is the (72 km/h). The relationship between might be attenuated by the Quebec pressure in Pa or N/m2, V is the wind the lateral displacement and the wind ρ Bridge itself and the small hill located speed in m/s, and air is the air den sity at speed squared was also reported in the to the east of the bridge. In fact, the sea level, approximately 1.255 kg/m3. latter study. average of the highest velocity east For numerical comparison, Table 4 winds were blowing from a direction presents the values of the predicted and Vertical Displacements with an azimuth of 65°. The wind the measured transversal displacements from this direction impacts directly (from the best-fit parabola). The last The original design plan of the the suspended span of the bridge values were calculated with the best fit Quebec Bridge [DRC 1908a,b] where the GNSS antenna is located parabola given above and the first shows the predicted vertical displace- and must pass above the hill and val ues (in metres) were calculated ment of the cantilever arm and the across the Quebec Bridge structure with this approximate estimation: suspended span for the same load 5 2 before reaching the anemometer. The 1.19 x 10 VT , where the coefficient is condition as described in the previ- average azimuth of the strongest west derived from the ratio of the maximal ous sub-section. At the middle of the wind was 255°. From this direction, predicted transversal displacement and suspended span, the predicted value the wind was directly measured the corre sponding wind speed squared was 2.2 in (5.6 cm) for a transversal (without obstruction) by the (0.343 m / (170 km/h)2). wind speed of 170 km/h. That is a anemometer and the wind can reach Overall, the differences between the positive value (upward direction) for the Quebec Bridge suspended span second best fit parabola (west winds the bridge windward side and a nega- with almost no obstruction, since the only) and the 1908 prediction were tive value (downward direction) for wind flow can pass over the hollow smaller, as seen in Figure 6. This fact is the leeward side of the bridge. This space of the suspension cables of the further evidence that the speed of the can be approximately modelled by Pierre-Laporte bridge. Direct meas- eastern wind, recorded by the the following relation: 1.94 x 10-6 2 urements of the wind at the top of the anemometer on the Pierre-Laporte VT , where the coefficient comes Quebec Bridge (especially the one suspension bridge, was attenuated as from the ratio of the maximal vertical from the east direction) could cer- compared with the eastern wind that predicted displacement and the corre- tain ly improve the R2 value of the blew at the location of the Quebec sponding wind speed squared best fit parabola reported in Table 3. Bridge’s suspended span. (0.056 m / (170 km/h)2). For a The original plan of the Quebec For comparison, let us note that for 100 km/h and a 50 km/h wind speed, Bridge [DRC 1908a,b] provided the the nearby Pierre-Laporte suspension the vertical displacements would be For personal use only. following interpretative remark: the bridge (1040 m in length), Santerre and 1.9 cm and 0.5 cm, respectively. maximum lateral deflection at middle Lamoureux [1997] reported an 8 cm The transversal wind speed must of the channel (suspended) span from transversal displacement at the center of be strong enough to be detected by 30 lb/ft2 of the wind load normal to the the suspension span provoked by a wind the measured GNSS vertical coordi- bridge plus the wind load on a passing speed of 25 km/h (7 m/s). Wong [2004] nate variations, since GNSS is less train on the channel (suspended) span. had measured a lateral displacement of precise in the vertical component This value was 13.5 in (34.3 cm). 46 cm for the wind speed of 26 m/s compared with the horizontal direc- According to Unsworth [2011], a wind (95 km/h) for the Tsing Ma bridge (over tion [Santerre 1991]. In fact, for the lateral force of 30 lb/ft2 is applying a the 1377 m suspended span). Wong also day with the highest wind speed wind pressure corresponding to the reported that the wind tunnel test confirms recorded (100 km/h), a vertical dis- maximum wind speed for safe opera- the proportionality with the wind speed placement of 2.8 cm was measured by tion of trains. This value corresponds squared. Nakamura [2000] report ed, for a GNSS, a value larger than the Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17 to a wind speed of about 170 km/h 720 m main span suspension bridge, a pre dict ed one of 1.9cm.

Table 4: Comparison of transversal displacements for different transversal wind speed values. Speed (km/h) 170 150 100 60 30 10 Speed (m/s) 47.2 41.7 27.8 16.7 8.3 2.8 1908 Prediction (cm) 34.3 26.8 11.9 4.3 1.1 0.1 Best fit (all) (cm) 34.6 ±0.9 28.2 ±0.7 15.0 ±0.4 7.0 ±0.2 2.6 ±0.07 0.4 ±0.04 Best fit (west wind) (cm) 32.0 ±1.2 25.7 ±1.0 13.0 ±0.5 5.8 ±0.2 2.1 ±0.09 0.5 ±0.04

306 GEOMATICA Vol. 70, No. 4, 2016 Movement Analysis assumed to be 0.000 006 1/°F. This temperature (Figure 7). Unfortunately, cor responds to 11.0 ppm/°C. With this no steel bridge temperature was avail- Caused by value, the displacements in mm for a able. In the time series, the train transit Temperature and 10°C temperature variation have been effect, which can be as large as 15 cm calculated; see Table 5 (line 3). The (see first section above), was removed Solar Radiation dimensions given in line 2 of Table 5 are in order to only keep the effect of also shown in Figure 1. tem perature on the vertical coordinate Table 5 (last line) shows the variations. In Figure 7, the pale blue length and height of the bridge steel Vertical dots represent the 10-min moving aver- variations (in inches) due to a temper- Displacements age vertical coordinate variations of the ature variation of -30°F to 120°F (for a GNSS antenna; the dark blue dots are total variation of 150°F, or 83.3°C) as The first effect of temperature the mean values for a complete day reported in DRC [1908a,b]. The value investigated was the vertical variation of associated with their corresponding of the steel thermal coefficient was the GNSS antenna with respect to the air daily mean air temperature. In this time

Table 5: Length (height and width) of the bridge variations (in mm) caused by a 10°C temperature variation using the theoretical steel thermal coefficient. L. arm ½ L. central H. main H. total H. central ½ bridge cantilever span tower central span span width 177.0 mm 97.5 mm 94.5 mm 69.5 mm 33.5 mm 15.3 mm 19.5 mm 10.7 mm 10.4 mm 7.6 mm 3.7 mm 1.7 mm * 6.34 in 3.50 in 3.40 in 2.52 in N/A N/A * Equivalent values in inches for a 150°F temperature variation (from DRC [1908a,b]). For personal use only. Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17

Figure 7: Vertical coordinate variation as a function of the (ambient) air temperature.

Vol. 70, No. 4, 2016 GEOMATICA 307 series, the daily mean temperature errors in the relative wet tropospheric Figure 8, representing two separate ranged from –23.6°C to 25.9°C, delay model, especially during summer weeks during the summer season 49.5°C temperature variation. where the relative humidity (partial (bottom) and the winter season (top). In general and as expected, when water vapor pressure) is high (in com- During the summer, the longitudinal the temperature is above 0°C, the parison with the winter season), and this variations remained very close to 0, ver tical variation is positive and vice effect is not totally cancelled in relative regardless of the positive temperature versa. A linear regression was estimat- (differential) positioning, especially value, but as soon as the temperature ed (the purple line in Figure 7) using the because the (closest) GNSS reference dropped below 0°C (roughly) during daily values. This provided a corre- station was located 7 km away with a winter, the variations became negative sponding thermal coefficient of height difference of 70 m with respect (displacements toward the south 9.3 ±1.5 ppm/°C (instead of the theoret- to the Quebec Bridge GNSS receiver. shore). This is an indication that the ical value of 11.0 ppm/°C) with a R2 Residual tropospheric errors mainly suspended span was blocked and value of 0.50 (although a small value, affect the GNSS height determination pulled by the south cantilever arm once the Fisher test was passed). The red line [Santerre 1991]. Moreover, no steel the (air) temperature was below about in Figure 7 represents the predicted temperature data were available, as 0°C. The cross-corre la t ion values at val ues calculated with the 11.0 ppm/°C pre viously noted. zero time lag, indicated in the lower thermal coefficient using the total left corner of the graphs, were indeed height of the suspended span (69.5 m). Longitudinal very large (0.93) for the weeks with For the 49.5°C total daily temperature Displacements negative temper a ture and smaller for variation during the year, the measured positive temperature (as low as 0.36 vertical variation was then 3.2 cm Since the GNSS receiver was located during the week in summer). versus 3.8cm for the predicted value at the middle of the suspended span, one For studying this phenomenon (for a discrepancy of 6 mm). might not expect any variation in the fur ther, a graph of the longitudinal To explain this discrepancy lon gitudinal coordinate. But some depar- coordinate variation as a function of (6 mm), one might suspect remaining tures were noticed, as illustrated in the air temperature is presented in For personal use only. Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17

Figure 8: Longitudinal variation and air temperature for one week in winter (top) and one week in summer (bottom).

308 GEOMATICA Vol. 70, No. 4, 2016 Figure 9. The large dots represent the value of 0.92 (in this case, the Fisher test and the cantilever arms were also daily mean values and the smalle dots was passed successfully). With respect replaced more than 10 years ago represent the 10-min moving average to the theoretical thermal coefficient of (around 2005). From Figure 8 and 9, it longitudinal variation of the GNSS 11.0 ppm/°C and for a temperature seems that an unusual displacement in antenna. This figure shows that the of –30°C (from 6ºC to –24ºC), one the longitudinal direction of the sus- longitudinal displacement occurred at should obtain a transversal variation pended span of the bridge still exists. 6°C instead of around 0°C. Then the of –9.0 cm instead of –7.2 cm (see data time series were divided into two Figure 9). It seems some part of the lon- Transversal parts: below (green dots) and above gitudinal displacement was absorbed by Displacements (blue dots) 6°C. The linear regressions the damping mechanisms (shock for both parts are also plotted in Figure absorbers) and the supports between the Particularly during sunny summer 9 (solid lines). suspended span and the anchor arms. It days, an important transversal varia- By dividing the slope of the linear is worth recalling that the tropospheric tion in the GNSS antenna coordinates regressions by the length of the can- error (mentioned in the previous section) was noticed. Some examples are given tilever arm plus half the length of the does not affect GNSS horizontal (longi- in Figure 10. In this figure, to avoid suspended span (275 m), a thermal tudinal and transversal) components. superposition of the different plots, the dilatation value of 0.2 ± 0.2 ppm/°C Interesting to note that L’Hébreux range of the solar radiations (right side was obtained with R2 value of only [2001] reported that eight pins used for scale) was set between 0 and 4 kW/m2 0.01 when the temperature was above linking the suspended span and the can- even when the maximum recorded 6°C. In this case, there was no signifi- tilever arms were replaced in 1985 value was 1.4 kW/m2, and the temper- cant correlation with temperature (as because the bridge expansion did not ature values (brown line), to be read indicated by the Fisher test). However, behave adequately. According to the with the left scale, have to be multi- when the air temperature was below Canadian National’s engineers (personal plied by 3 to obtain the real air temper- 6°C, the corresponding thermal dilata- communication), the dampers (shock ature in °C. The time is indicated in tion was 8.3 ± 0.3 ppm/°C with R2 absorbers) between the suspended span hours in local time (LT), that is, For personal use only. Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17

Figure 9: Longitudinal coordinate variation as a function of the air temperature.

Vol. 70, No. 4, 2016 GEOMATICA 309 Eastern Time zone. In order to isolate is also related to the sun orientation with Summary, the effect of solar radiation, only the respect to the bridge structure (which days with low transversal wind (less creates a temperature difference between Conclusions and than 30 km/h) were selected, which both sides of the bridge) and the thermal Recommendations also affects transversal coordinate inertia of steel. variations (see previous section). Let us mention that solar radiation Table 6 compiles the movements The transversal displacements effects have been reported for bridge of the suspended span of the Quebec could easily reach up to –5 cm before towers and telecommunication towers. Bridge measured by GNSS, as reported noon and a bit less (about 3 cm) in the For example, Schenewerk et al. [2006] in the previous sections, along with the afternoon during summer sunny days, have shown a tower lateral variation of calculations (larger expected deforma- in which solar radiation values were as 9 cm due to differential temperature for tions) made by the Quebec Bridge high as 1 kW/m2, as in the examples the Sunshine Skyway bridge (with tow- engineers who designed it more than a presented in Figure 10. The rapid vari- ers 132 m in height), located in Tampa century ago. ation in the solar radiation during the (Florida). Breuer et al. [2008] studied The freight train load causes the day indicates the presence of clouds. the daily and seasonal drift of the centre of the suspended span to sub- In fact, during cloudy days the trans- Stuttgart TV Tower caused by the daily side by up to 17 cm. This measured versal displacements were signifi- solar radiation and air temperature vari- value is in fair agreement with the cant ly reduced (and of course at night ation. During a sunny day, the surface value assumed by engineers during the there is no solar radiation). During the of the tower concrete shaft that was design and the construction of the winter season, the sun’s elevation exposed to sunlight was subjected to Quebec Bridge. The subsidence value angle is always low (maximum 21° the thermal expansion provoked by is smaller for passenger trains (ranging during the winter solstice), and there- non-symmetrical warming. The side between 1.0 and 2.5 cm). The train fore the transversal displacement was exposed to the sun would extend, and transits also provoke a tilt to the sus- always close to 0. Indeed, the transver- the tower and its top would incline pended span since the railway is located sal displacement due to solar radiation away from the sun. on the upstream side of the bridge. The For personal use only. Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17

Figure 10: Variations in the transversal coordinate and solar radiation for six different days.

310 GEOMATICA Vol. 70, No. 4, 2016 maximal transversal displacement of deck level. Longitudinal wind load does suggest recording GNSS data with a the GNSS receiver, located 34 m not affect the suspended span of the higher data rate (some receiver models above the railway, was 11 cm. The lon- Quebec Bridge. can measure at a rate of 100 Hz). Since gitudinal displacement (of about 1 cm) The impact of the temperature GNSS signals are blocked by metallic of the suspended span was also detect ed varia tion on the vertical movement of the structures, the authors also recom- for freight train transits, but not for GNSS antenna located at the centre of mend complementing GNSS measure- passenger trains. Car loading effect the suspended span of the Quebec Bridge ments with other sensors, such as was not detected by the GNSS antenna was measured at a slightly smaller value accelerometers and total station reflec- that was located on top of the (3.2 cm versus 3.8 cm, a 6-mm discrep- tive prisms, installed at the deck level. sus pend ed span of the Quebec Bridge. ancy) compared with the predicted one. Finally, an anemometer should be It was also shown that the center One can suspect the GNSS height deter- installed directly on the Quebec of the suspended span reacts instanta- mination to be affected by errors in the Bridge to measure the real parameters neous ly to transversal wind load and wet delay modelling during the summer of wind (speed and direction) acting the transversal displacement is propor- time because the nearest GNSS reference on the bridge as well as the installation tional to wind speed squared. The station is located 7 km away with a 70 m of steel temperature sensors at strategic measured values can reach 13 cm for height difference. A blockage of the sus- points of the bridge. wind speed of 100 km/h. The extrapo- pended span with the south cantilever lated value fits very well with the pre- arm was measured when the temperature dicted value made during the stage of drops below 6°C. The magnitude of this the bridge design. longitudinal displacement reached 7 cm Acknowledgements The relationship between vertical for a temperature variation of 31°C. displacements of the suspended span Transversal displacement of the GNSS Firstly, we want to gratefully and the transversal wind speed has not antenna easily reached up to 5 cm because thank the Port of Montreal for giving been demonstrated. To detect this of the high solar radiation values (up to us the access to the GNSS receiver effect using the GNSS technique, the 1 kW/m2) during summer days. This phe- data as well as their partners in this authors recommend the installation of nomenon can be explained by the differ- project, the Canadian Coast Guard, the a reference GNSS station closer to the ential temperature values between the two Canadian Hydrographic Service and bridge and another GNSS antenna on sides of the Quebec Bridge. CN (Canadian National Railway the other side of the suspended span For a complete geodetic deformation Company). The authors were also of the Quebec Bridge. In this last monitoring of the Quebec Bridge, the offered free access to the complemen- configuration, for such a short base- addition of GNSS receivers on each side tary data described in this paper by the line of 31 m (equal to the bridge of the suspended span and on top of the Quebec Department of Transportation, For personal use only. width), GNSS will be able to meas- main towers is recommend ed, along with MeteoLaval and Cansel. We are very ure the inclination of the suspended the installation of inclinometers. In order thankful for their collaboration. span even if GNSS height accuracy is to improve the GNSS determination, Finally, NSERC (Natural Science and less than the horizontal accuracy. especially in the vertical component, the Engineering Research Council of Another possibility is to install digi- authors suggest installing closer refer- Canada) is acknowledged for its tal inclinometers (tilt sensors) on the ence GNSS stations. To study the natural research grant that was used to suspended span at the top and at the frequencies of the bridge, the authors par tial ly fund this research.

Table 6: Comparison of the GNSS measurements and the 1908 original design calculations. Load Direction 1908 design calculation GNSS measurements

Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17 Vertical 34 cm (two trains) 17 cm (one freight train) Train Transversal N/A 11 cm (at the top of the span) Longitudinal N/A 1 cm

Car Vertical N/A Not significant (not detected) Wind Vertical 2 cm (at 100 km/h) 3 cm (at 100 km/h) Transversal 34 cm (at 170 km/h) 32 cm (extrapolated at 170 km/h) Temperature and solar Vertical 3.8 cm (for 50°C variation) 3.2 cm (for 50°C variation) radiation Transversal N/A 5 cm (for high solar radiation) Longitudinal N/A 7 cm (at –25°C)

Vol. 70, No. 4, 2016 GEOMATICA 311 References Surveying Engineering. 121(1): 35–40. Trimble. 2012. Trimble HD-GNSS processing. Nakamura, S. 2000. GPS measurement of Trimble Survey Division White Paper. wind-induced suspension bridge girder Unsworth, J.F. 2011. Railroad bridge Breuer, P., T. Chmielewski, P. Górski, displacements. Journal of Structural design criteria. Chapter 11 in E. Konopka and L. Tarczynski. 2008. Engineering. 126(12): 1413–1419. Structural Steel Designer’s Handbook The Stuttgart TV Tower displacement Santerre, R. 1991. Impact of GPS satellite (5th Edition). R.L. Brockenbrough of the top caused by the effects of sun sky distribution. Manuscripta and F.S. Merritt, Eds. and wind. Engineering Structures. Geodaetica. 16(1): 28–53. USACE. 2002. Structural deformation 30(10): 2271–2781. Santerre, R., L. Lamoureux. 1997. Modified surveying. Chapter 8: Monitoring DeLoach, S.R. 1989. Continuous deforma- GPS-OTF algorithms for bridge moni- structural deformation using GPS. tion monitoring with GPS. Journal of toring: application to the Pierre- Engineering Manual—US Army Surveying Engineering. 115(1): 93–110. Laporte suspension bridge in Quebec Corps of Engineers EM 1110-2-1009. DRC, Department of Railways and Canals. City. Proceedings of the International Wong, K.-Y. 2004. Instrumentation and 1908a. The Quebec Bridge. Report of Association of Geodesy Scientific health monitoring of cable-supported the Government Board of Engineers Assembly, IAG Symposium 118: bridges. Structural Control and Volume I, 259 Available from 381–386. Health Monitoring. 11: 91–124. http://www.historicbridges.org Santerre, R. 2011. Use of GPS for bridge Xia, H., Y.L. Xu and T.H.T. Chan. 2000. DRC, Department of Railways and Canals. deformation monitoring. GPS Chapter. Dynamic interaction of long suspen- 1908b. The Quebec Bridge. Volume in Monitoring Technologies for Bridge sion bridges with running trains. II. Plates to accompany Volume I of Management, Eds. B. Bakht, A. Mufti Journal of Sound and Vibration. the Report of the Government Board and L.D. Wagner. 173–205. 237(2): 263–280. of Engineers. Available from: Schenewerk, M.S., R.S. Harris and Xu, Y.L., B. Chen, C.L. Ng, K.Y. Wong http://www.historicbridges.org J. Stowell. 2006. Structural health and W.Y. Chan. 2010. Monitoring Hyzak, M. and M. Leach. 1995. Bridge monitoring using GPS—observing the temperature effect on a long suspen- monitoring by GPS. Surveying World. Sunshine Skyway Bridge. March- sion bridge. Structural Control and 3(3): 8–11. April. 18–25. Available from: Health Monitoring. 17(6): 632–653. L’Hébreux, M. 2001. Le pont de Québec. http://bridgesmagazine online.com Yi, T.-H., H.-N. Li and M. Gu. 2012. Ed. Septentrion. 255. Smadi, Y. 2015. Étude sur l’utilisation du Recent research and applications of Lovse, J.W., W.F. Teskey, G. Lachapelle and système GNSS pour l’auscultation GPS-based monitoring technology M.E. Cannon. 1995. Dynamic defor- topographique du pont de Québec. for high-rise structures. Structural mation monitoring of tall structure MSc Thesis, Department of Geomatics Control and Health Monitoring. using GPS technology. Journal of Sciences, Laval University. 20(5): 649–670. q For personal use only. Geomatica Downloaded from pubs.cig-acsg.ca by Université Laval Bibliotheque on 05/05/17

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