Experiences from Timber Bridge Inspections in Sweden – Examples of Influence of Moisture

Experiences from timber bridge inspections in Sweden – examples of influence of moisture

Anna Pousette, Per-Anders Fjellström

SPSveriges Tekniska Forskningsinstitut

SP Rapport 2016:45

Experiences from timber bridge inspections in Sweden – examples of influence of moisture

Anna Pousette, Per-Anders Fjellström

Abstract

This report contains a compilation of experiences that SP Technical Research Institute of Sweden has obtained from inspections of timber bridges for bridge owners. The report has been prepared within the project DuraTB – Durable Timber Bridges.

Details of timber bridges are described, the focus is on timber railings and stress- laminated decks, because of the importance of good wood protection by design in these areas. Several examples are described with type of bridge and location, materials and dimensions, moisture contents and rot propagation and probable cause of the damage.

Key words: timber bridge, stress-laminated decks, moisture content, bridge inspection

SP Sveriges Tekniska Forskningsinstitut SP Technical Research Institute of Sweden

SP Rapport 2016:45 ISBN 978-91-88349-49-1 ISSN 0284-5172 Borås 2016

Contents

1 Introduction 6 1.1 Timber bridge inspections in Sweden 6 1.2 Measured moisture contents 7

2 Summary of inspection results 8 2.1 Beam bridges 8 2.2 Stress-laminated deck plates 9 2.3 Stress-laminated box-beam and T-beam bridges 10 2.4 Trusses, arch bridges, suspended bridges and cable styed bridges 11 2.5 Comparison with earlier inspection project in Sweden 11 2.6 Comparison with bridges in Norway 12

3 Details – influence of moisture 14 3.1 Example 1 – Railing post 14 3.2 Example 2 – Railing post 16 3.3 Example 3 – Railing panel 19 3.4 Example 4 – Railing panel 21 3.5 Example 5 – Stressed laminated timber deck 23 3.6 Example 6 – Stressed laminated timber deck 25 3.7 Example 7 – Stressed laminated timber deck 27 3.8 Example 8 – Stressed laminated timber deck 30 3.9 Example 9 – Stressed laminated timber deck 33 3.10 Example 10 – Stressed laminated timber deck 36 3.11 Example 11 – Stressed laminated timber deck 39

4 References 41

Appendix A. Moisture measurements on timber truss bridges from Martinsons 42

Preface

This report has been prepared within the project DuraTB – Durable Timber Bridges. The objectives of the project are to develop sustainable timber bridges by developing guidelines for moisture design methods and new and improved structural designs and bridge details with respect to durability and maintenance aspects.

The project DuraTB is a Wood Wisdom-net project with participants from Norway, Finland, Sweden and USA. Project manager is Kjell Arne Malo, NTNU, Norway. The project has been funded under the WW-net+ Research Programme by the ERA-NET Plus Scheme of the Seventh Framework Programme (FP7) of the European Commission. The Swedish participation has been funded by Vinnova and industry partners Martinsons Träbroar, Moelven Töreboda, Limträteknik and Trafikverket.

This report contains a compilation of experiences that SP Technical Research Institute of Sweden has obtained from inspections of timber bridges for bridge owners during several years. The report is part of WP2 “Performance based service life design of timber bridges”, managed by Sven Thelandersson, Lund University, and is a result from task 2.1 “Collection of field data from existing instrumented bridges” that Anna Pousette, SP Technical Research Institute of Sweden, is responsible for.

1 Introduction

Improved guidelines to avoid the risk of moisture damages is one of the goals of the project Durable Timber Bridges. Data concerning actual service life performance of existing timber bridges can be used as a basis to evaluate today’s bridges and to develop new designs and new design tools.

Field data regarding moisture content and temperature in timber bridges together with information about the bridges and the climate of the sites can be used to calibrate calculation models of moisture distribution in timber.

To validate tools for service life design it is likewise useful to have field data regarding moisture content and temperature, but also information concerning actual service life performance from inspections. Any damages that has occurred in existing bridges are valuable. This report describes some results from timber bridge inspections in Sweden, carried out under the ordinary bridge management (1). It includes a compilation of bridge damages at the time of inspections. Some examples with measurements and assessments of damages are included. They show moisture content levels measured at different areas in bridges together with descriptions of where and in which extent a rot development has been observed.

Inspections of some Swedish timber bridges were also made in an earlier project in 2004 (2). The bridges were selected to include different bridge types, ages and geographical locations. No serious damages, which should affect the bearing capacity of the bridges over the next 10 years, were found. However, there were some details and moisture levels which in the longer term should be taken care of. The inspected bridges had several damages due to lack of detailed workmanship or unsuitable materials, which have then been improved in later bridges. Some comparisons with the earlier study are made in chapter 2.5.

Inspections and evaluations of timber bridges have of course also been carried out in other countries. There are many timber bridges built in Norway over the last 25 years (3). They have used somewhat different materials, treatments and constructions compared to Sweden but it may still be interesting to compare the experiences, see chapter 2.6.

The timber bridge manufacturer Martinsons has built many timber truss bridges for pedestrians/cyclists. They made a follow-up of some truss bridges in Sweden in 2009, when the bridges were 8-12 years old. Moisture was measured during one day, see Appendix A.

1.1 Timber bridge inspections in Sweden

During 2011 to 2015 SP Technical Research Institute of Sweden inspected about 145 timber bridges built after 1990. The inspections were made on behalf of the Swedish Transport Administration, local authorities or engineering consultants. The bridges were geographically spread all over Sweden, from Lund in the south to Kiruna in the north, but most were located in the northern parts of Sweden.

The bridges presented in this report is not a random selection from all timber bridges in Sweden. It contains only a minor part of the results from bridges that have been inspected by SP, mainly as part of the planned bridge management. In chapter 3 Details, the focus is on timber railings and stress-laminated decks, because of the importance of good wood protection by design in these areas.

The inspected bridges were built during 1990-2015 and included 27 beam bridges (plus 12 older beam bridges); 66 stress-laminated deck bridges; 10 stress-laminated box-beam bridges; 9 stress-laminated T-beam bridges; 30 bridges of other types like trusses, suspended and cable-stayed bridges, etc. This report describes the type of damages at the time of inspection, but not the Condition Class. The Swedish Transport Administration has four classes 0-3 for the condition of a bridge, see table 1.1, and the requirement is a main inspection of bridges every six years.

Table 1.1. Condition classes of bridges in Sweden (4) Condition class Definition 0 Malfunction beyond 10 years 1 Malfunction within 10 years 2 Malfunction within 3 years 3 Malfunction at the time of inspection

The documented deficiencies in this report required measures ranging from immediately to within ten years.

1.2 Measured moisture contents

In this report the values of moisture content are the values measured at the time of inspection. Moisture content values reported as high moisture values in this report are over 20% MC. Serious moisture levels in wood are above saturation point, which for spruce and pine is 25-30 %. Long periods with MC above the critical value of 25 % can cause problems with rot in the wood. Continuous measurements or measurements repeated often can give more accurate data, since measurements taken for example directly after a rainy day might not be representative if the wood has the possibility to later dry out. But data from the inspections can still provide valuable information if you also take into account the structure and location of the bridge. And MC from different depths in the wood can give information if the measured moisture is only temporary on the surface after rain or is spread into the whole wood element and probably will not dry out so quickly.

The moisture content in wood vary naturally with the seasonal variation of humidity of the air. The cause of the measured high moisture contents are typically condensation, rain or running water, and not high relative humidity of the air, but the reason for the high MC can sometimes be difficult to determine when bridge inspections are infrequent. To really understand the reasons for the high MC, measurements should be carried out more frequently. Also inspections on rainy days can provide more information and show how water spreads on the bridge. For bridges crossing over rivers the underside of decks can be influenced by evaporated water from river that can condensate. The distance from water can in these cases be an important factor for the MC at the bottom part of a bridge deck.

The measured high MC are usually connected to the details, but also sometimes to tear or cracks in the wood. The bridge details have been developed constantly since the first modern timber bridges were built in Sweden in the early 1990s. Today the knowledge about constructive wood protection is used more widely and also requirements and recommendations from the Swedish Transport Administration have are more rigorous. Examples are claddings on beams and arches and the use of spacers and treatment of end grain. Therefore some of the reported deficiencies and damages will probably not occur in newer bridges at all.

Most commonly impregnated pine is used in unprotected bridge components like beams and railings. The stress-laminated bridge decks are on the other hand typically made of spruce. Impregnation affect moisture measurements and it can be difficult to know the exact moisture content in large beams, as there is a mix of impregnated sapwood and untreated heartwood in glulam.

2 Summary of inspection results

About 950 timber bridges have been built in Sweden since 1990. During 2011-2015 SP in Skellefteå have inspected about 145 of these bridges. The bridges are geographically spread all over Sweden. They are both road bridges and pedestrian bridges and built with different structures for example girder bridges, stress-laminated decks, stress-laminated box-beam and T-beam bridges, trusses, suspended and cable-stayed bridges.

General damages of many of the inspected timber bridges were in addition to those specified below for each bridge type: • Damages from snow removal vehicles • Flaking of paint on painted members • Algae on the surfaces • Cracks and sometimes blisters in asphalt paving • Bushes and other vegetation at or near the superstructure • Soil or gravel on bridge members or foundations

Most deficiencies were found on bridges built from 1990 to 2008. It can be expected that older bridges will get more damages due to aging, but from these inspections it is difficult to assess the time until maintenance or repair actions are needed, because during the same period the bridge designs have been improved a lot.

2.1 Beam bridges

Timber beam bridges are frequently used as pedestrian bridges, but also sometimes as road bridges especially on smaller roads. The beams are usually made of salt-impregnated pine. The bridges are often built with an open design with a wooden plank deck. Today the beams are normally covered on the outer sides, but earlier bridges had no weather protection and the outer beams often have many cracks on the outside. Recently some bridges have also been built with spruce beams covered with cladding on the outside to protect them from weather impact.

Inspected bridges were 10 road bridges (including also four bridges built 1737-1965) and 20 pedestrian bridges (including also six bridges built 1930-1989). At the inspections many bridges had cracks on unprotected and weather exposed beam surfaces, and the color of surface treatment had impact on the cracking. Not working joints/expansion joints at abutments in combination with no removal of soil and dirt from abutments for some bridges resulted in high moisture contents at the ends of main beams. Half of the beam bridges had cracks and the same amount of bridges had high moisture contents. Nearly half of the road bridges and one pedestrian bridge had rot.

Table 2.1. Results from 27 inspected beam bridges, built 1990-2013. Deficiencies in Road bridges Pedestrian bridges beams/girders (6) (21) Cracks 5 9 High moisture content 2 14 * Rot - 2 *At least three of these bridges are made of spruce

Figure 2.1. Beam with typical cracks. Figure 2.2. Beam end with high moisture content

2.2 Stress-laminated deck plates

The stress-laminated deck plates are made of spruce, and usually have an asphalt surface, but sometimes gravel or wood on the surface. Stress-laminated deck plates are common for both road bridges and pedestrian bridges, and sometimes in combination with other structural elements, for example various trusses or arches. The bridges were built with wooden railings, but steel railings are required today for road bridges.

Development of deck plates since the 1990´s has led to several important improvements such as better anchor plates and better coverage of the edges of deck plates. Timber bridge manufacturers have developed their own guidelines for the execution of waterproofing, and newer bridges have better quality.

Inspected bridges were 36 road bridges and 31 pedestrian bridges. At the inspections the sealing of the waterproofing layer at the edge was poor on several bridges, and this led to high moisture contents and sometimes rot on stress-laminated deck plates that were built from 1994 to about 2001. Bad sealing around railing posts results in drainage water running down the posts causing high moisture contents at the edges of the decks.

Some problems with anchorage of the pre-stressed steel bars was observed. Aluminum plates had cracks; vertical hardwood anchor plates made of two separate pieces were too weak and bent. Newer bridges have larger horizontal hardwood anchor plates to spread the load in a better way.

Rhombic deck plates had potholes in asphalt paving where anchor plates of the pre- stressed steel bars were located. Leaking end joints/expansion joints resulting in water on the foundation. This led to high moisture content at the corners of some deck plates which can affect their durability. Cupping of some deck plates was observed.

Table 2.2. Results from 67 inspected bridges with stress-laminated decks, built 1994- 2015. Deficiencies found in stress-laminated Road bridges Pedestrian bridges decks. (36) (31) Cupping, 1994-2014 16 15 High moisture content, 1994-2015 8 13 Rot, 1994-2000 2 6 Cracks in stress-bar anchor plates, 2000-2004 4 5

Figure 2.3. High moisture contents, indirect Figure 2.4. Two piece hardwood plates damages were rail posts inclined inwards works poorly, they bend and due to that and the asphalt coating started to crack the aluminum plate cracks. along the edge. The leakage came from inadequate execution at the edge beam and the rail posts.

Figure 2.5. High moisture content and rot. Leakage from the attachement of rail posts and inadequate execution at the edge beam.

2.3 Stress-laminated box-beam and T-beam bridges

Inspected bridges were 4 road bridges and 10 pedestrian bridges. There are few and quite new box-beam bridges and T-beam bridges, and not so many damages reported. Mostly the same problems occurred as for stress-laminated deck plates, with cupping, moisture, sealing at edges and with anchor plates. No decks had rot.

Table 2.3. Results from 19 inspected bridges with stress-laminated box and T-beam decks, built 1993-2015. Deficiencies found in stress laminated box Road bridges Pedestrian bridges and T-beam decks. (9) (10) Cupping, 1994-2008 - 3 (T-beam) High moisture content, 1993-1997 2 (T-beam) 3 (T-beam) Rot - - Cracks in stress-bar anchor plates, 2003 2 -

2.4 Trusses, arch bridges, suspended bridges and cable styed bridges

Most of these types of bridges have been in quite good condition at inspections. They are often built with a bridge deck of beams or a deck plate. Inspected bridges were 5 road bridges (including 3 suspended bridges built 1920-1981 and 1 arch bridge from 1889) and 21 pedestrian bridges (including 1 bridge from 1920). Many damages were the same as occurred for beam bridges and stress-laminated deck plates. Cracks, cupping and high moisture content were the most common damages. Rot was found in two bridges and asphalt damages in three bridges.

Table 2.4. Number of trusses, arch bridges, suspended bridges and cable styed bridges with reported damages Damage Road bridges Pedestrian bridges Cracks 1 4 Cupping - 3 High moisture content 1 9 Edge beam 1 3 Anchor plate/ aluminum plate - - Plywood anchor plate - 2 Rot 1 1 Asphalt surface - 3

2.5 Comparison with earlier inspection project in Sweden

Some Swedish timber bridges were inspected in an earlier inspection project in 2004. The 13 timber bridges were chosen based on different bridge types, ages and geographical locations. The bridges were built 1994-2001. Timber bridge structures were developed very much during 1994-2001, and much improvement work was done to find good design solutions. The inspected bridges had some damages due to lack of detailed workmanship or unsuitable materials, which has been improved in later bridges.

No serious damages were found, which should affect the bearing capacity over the next 10 years from inspection, however, there were details and moisture levels which in the longer term should be taken care of. The highest moisture contents were measured in unprotected cross beams, main beams, arches and pillar supports, in railings especially at the bottom of the railing posts, and at the end or edge of deck plates.

At abutments was a lot of soil, dirt and leaves, and sometimes a lot of vegetation around them. Expansion joints between road and bridge had some damages resulting in leakage

of water, gravel and dirt onto the abutments, which affected the deck plates or beams at the ends. There were also some bridges with bad contact with the abutments, loosened or damaged bolts or bracings.

Several beams, arches and other structural elements had delamination and/or cracks on painted surfaces, especially on south sides. Some steel covers were damaged and the surface treatment was often eroded and with some cracks on the outer weathered sides of structural parts. No repainting had been made, just small touch up on small areas. High moisture contents occurred at some unprotected and exposed parts.

Several stress-laminated deck plates had anchor plates pressed into the wood and the wood was deformed and crushed around the anchor plates. Forces in pre-stressing rods were reduced since the bridges were built, but this is normal and they were still at acceptable levels. There was a lot of vegetation around some deck plates, and some gutters were not cleaned.

Some railings had broken railing boards, loosened nails and gaps in the railings. The surface treatment of wooden railings was often quite worn, with flaking, cracking and with algae, and there were some rusty screws. Mechanical damages of plowing were found on several railings.

Commonly some loosened or insufficiently tightened bolts were observed on several bridges. Some joints were made with too small washers, which had been pressed into the wood and damaged the wood grain. Especially wood screws and the ends of threaded rods were corroded and also nuts and washers that were not galvanized were found.

A comparison of the quantity of damages reported at inspections in 2013-2014 and 2004 shows that damages with cracks, high moisture contents, edge beams and asphalt surfaces have been reduced since the earlier inspections. This can be a result of improved bridge design during later years. But also of course the different selection of the bridges and the different number of inspected bridges may influence the comparison. High moisture contents are still found in many bridges at the later inspections and sometimes also rot have been detected which was not the case in 2004.

2.6 Comparison with bridges in Norway

In Norway The Norwegian Public Roads Administration has gathered information from inspections, operation and maintenance and plan to use this to improve future timber bridges and to be a basis for preparation of standardized bridge details.

Most of the details where problems have occurred in Norwegian bridges are similar to reported damages from the Swedish inspections, but some damages do not occur in Swedish timber bridges because of different construction techniques and materials. The main difference is the use of creosote impregnation in Norway.

Table 2.6. Risk/damage of details in Sweden and Norway Risk/damage of detail Norway Sweden Deck encased in the abutment X - Deck surrounded by concrete strings at the abutment X (X) Water at end grain at abutment X X Accumulation of water and wetting on bearing X X Inclined ends of deck plate (rhombic deck) X X Cracks in wearing surface at deck ends X X

Constructive protection of end grain at deck ends X X Plants and bushes at abutments X X Railing posts attached to deck side X X Water runoff from edge to underlying parts - failure in edge X X fitting and missing drip at deck edge Connection through steel fittings – penetration of X X constructive protection Accumulation of dirt and snow etc. on cross beams X X Encasement of water at arch and pillar ends X X Standing water in lower joints with slotted -in plates X ? Water runoff along pillars into connections X X Water on deck due to missing transverse or longitudinal X ? incline Crushing of wood under anchor plate X X Failure to protect whole surface treatment with splints X ? Cracking X X Sealing with sealant that shrinks X ? External steel plates on the outside of the wooden parts X ? Runoff of copper ions on to e.g. galvanized steel X - Leakage of water at elevated curb X ? Creosote spills X - Wetting due to attached cables along outside of bridge X ?

Figure 2.6. Bridge details from Norway with creosote treated wood

3 Details – influence of moisture

Most damages recorded at the inspections of timber bridges are connected to high moisture levels, such as cupping of deck plates, problems with edge beams, anchor plates and asphalt surfaces and of course rot. Depending on the moisture level, increased moisture content in the wood can provide dimensional changes when the wood swells and long periods with high moisture contents above 25% provide suitable environment for decay fungi to grow. A reduction in moisture content may on the other hand mean that the wood shrinks and probably cracks. In outdoor climate in Sweden the moisture content in wood is normally between 14 and 20 %.

Rot decay includes many rot fungi, brown rot, white rot and soft rot. In these inspections usually the type of fungi was not determined. The rot propagation was determined by piercing with a knife and in some cases with drills.

The resistance to rot of heartwood of spruce and pine is better than of sapwood. Heartwood of pine has the best resistance, but sapwood of pine has the lowest resistance. Both sapwood and heartwood can normally be included in construction timber and glulam. Salt impregnation of timber with fungicides that give good resistance to rot is only made in sapwood of pine, as impregnation agents do not penetrate into heartwood of pine or into spruce. Salt impregnated sapwood has considerably better resistance than heartwood of pine.

3.1 Example 1 – Railing post

3.1.1 Type of bridge and location

Built: 2006 Construction no: BatMan no: 40-4015-1, Martinsons no: 5922-B. Type: Road bridge over water on a gravel road. Construction: Stress-laminated glulam deck and timber abutments. Age at inspection: Six years. Maintenance or reconstruction: No. Location/coordinates RT90: Bjurholm, X7096290, Y1647560 Local climate Open forest Weather data: No

Figure 3.1. Bridge

3.1.2 Materials and dimensions

Railing posts: Glulam L40, Spruce (Pica Abies ). Dimension: 115 x 180mm Surface treatment: Primer with fungicide, two layers of non-transparent glazing paint. Connections: M16 washers Ø18 x 75 x 6mm. Distances: Polythene washers Ø18 x 90 x 20mm.

Figure 3.2. Detail of abutment and railing post connection.

3.1.3 Moisture contents and rot propagation

M.C: Lower part of posts, over FSP. Top end of posts 16-20%. Area with decay: Lower part (0,5m) of one of the railing post, north east side.

Figure 3.3. Left picture north east side, decay in lower part of post. Right picture shows the north west side, no visible decay in the posts.

3.1.4 Cause of the damage

Material: Spruce is used instead of a more durable material like treated pine. Distances: Painted wooden board instead of polythene washers (18x90x20mm) between abutment and railing posts. Other: Railing posts are partly over filled with gravel at the north side of the bridge.

3.2 Example 2 – Railing post

3.2.1 Type of bridge and location

Built: 2007. Construction no: Moelven no: 07-BR-176A. There are two identical bridges at the same site, one short with several deficiencies and one longer in good condition. Type: Pedestrian bridge over water. Construction: Glulam girder bridge with glulam deck. Age at inspection: 7 years Maintenance or reconstruction: No Location/coordinates RT90: Ekerö, 6573703, Y1612203 Local climate: Water front. Weather data: No

Figure 3.4. The short bridge with several deficiencies.

3.2.2 Materials and dimensions

Railing posts: Glulam L40, Spruce (Pica Abies ). Dimension: 90 x 135mm. Surface treatment: Primer with fungicide, two layers of non-transparent glazing paint. Connections: M16, washers Ø18 x 75 x 6mm. Distances: Wood and sheet metal cladding.

Figure 3.5. Section of the bridge superstructure.

3.2.3 Moisture contents and rot propagation

M.C: Lower part of posts, over FSP. Top end of posts 16-20%. Area with decay: Crossing point between deck and railing posts.

Figure 3.6. The short bridge on the left picture, sheet metal cladding is missing and wooden distance have severe decay damages. Correct installation on the right picture, no damages on the long bridge.

Figure 3.7. The short bridge on the left picture, sheet metal cladding is missing, decay in railing posts. Correct installation on the right picture, no decay in railing posts on the long bridge.

3.2.4 Cause of the damage

Material: Spruce is used in the railing posts instead of a more durable material like treated pine. Construction work: The construction of the short bridge on site has been a seriously botched job on the part of the contractor. Many critical details are not done according to the drawings. Wood protection by design: Missing sheet metal cladding.

3.3 Example 3 – Railing panel

3.3.1 Type of bridge and location

Built: 1996. Construction no: BatMan no: 2-1816-1, Martinsons Type: Pedestrian bridge over road. Construction: Arch bridge with stress-laminated glulam deck. Age at inspection: 19 years. Maintenance or reconstruction: No Location/coordinates RT90: Vaxholm, X6590565, Y1642588 Local climate: Shaded north slope. Weather data: No

Figure 3.8. Bridge

3.3.2 Materials and dimensions

Railing panel: Treated pine (Pinus Silvestris ), NTR class A. Dimension: Shown in figure 3.9. Surface treatment: Two layers of primer with fungicide, two layers of non-transparent glazing paint.

Figure 3.9. Section of railing.

3.3.3 Moisture contents and rot propagation

M.C: Lower part of panel, over FSP, top 17-24%, measured in the heart-wood Area with decay: None

Figure 3.10. East side of railing panel, paint erosion on all parts but no visible signs of decay.

3.3.4 Cause of the damage

Paint erosion: Poor maintenance.

3.4 Example 4 – Railing panel

3.4.1 Type of bridge and location

Built: 2004. Construction no: BatMan no: 1490-215-1, Svenska Träbroar (Martinsons) no: 5637/D. Type: Pedestrian bridge, over road. Construction: Stress-laminated glulam deck. Age at inspection: 11 years. Maintenance or reconstruction: No Location/coordinates RT90: Borås, X6400427, Y375340. Local climate: South slope. Weather data: No

Figure 3.11.Several panels have been replaced with plywood boards due to decay in the original railing panels.

3.4.2 Materials and dimensions

Railing panel: Spruce (Pica Abies ). Dimension: Shown in figure 3.12. Surface treatment: One layer of primer with fungicide, one or two layers of non-transparent glazing paint.

Figure 3.12. Section of railing.

3.4.3 Moisture contents and rot propagation

M.C: Bottom, over FSP, top 15-19% Area with decay: Decay in lower rails and in the lower part of most of the pickets.

Figure 3.13. Severe decay in the lower part of the railing panels.

3.4.4 Cause of the damage

Material: Spruce is used instead of a more durable material like treated pine. Wood protection by design: Water trap between pickets and lover panel rail.

3.5 Example 5 – Stressed laminated timber deck

3.5.1 Type of bridge and location

Built: 1993. Construction no: BatMan no: 40-371-1, Svenska Träbroar (Martinsons) no: 4003/B. Type: Road bridge, over small stream. Construction: Stress-laminated glulam T-section deck. Age at inspection: 20 years Maintenance or reconstruction: No Location/coordinates RT90: Stöverfors, close to Skellefteå, X7194352, Y764797 Local climate: Forest Weather data: No

Figure 3.14. Stress-laminated glulam T-section deck.

3.5.2 Materials and dimensions

Glulam: L40, treated pine ( Pinus Silvestris ), NTR class A. Dimension: Deck 225mm. Girders 190.x.585mm. Surface treatment: Oil.

Figure 3.15.Section of superstructure.

3.5.3 Moisture contents and rot propagation

M.C: Over FSP. Along the top edges of the deck. Girders15- 17%, measured in the heart wood. Area with decay: None.

Figure 3.16.The edges of the deck are exposed to drainage water at both sides of the deck, resulting in plant growth and high moisture content. Crushing damage in the wood by the pre-stressing anchor plates. The girders are dry, protected by the deck.

3.5.4 Cause of the damage

Wood protection by design: None Maintenance: None

3.6 Example 6 – Stressed laminated timber deck

3.6.1 Type of bridge and location Built: 2000. Construction no: BatMan no: 21-237-1, Svenska Träbroar (Martinsons) no: 5308/B Type: Pedestrian bridge, over small stream. Construction: Stress-laminated plank deck. Age at inspection: 12 years Maintenance or reconstruction: No Location/coordinates RT90: Lumnäs, X6836882, Y1561020 Local climate: Water front, forest Weather data: No

Figure 3.17. Bridge elevation.

3.6.2 Materials and dimensions

Deck planks: Spruce K30 (Pica Abies). Dimension: 72x285mm. Surface treatment: One layer of primer with fungicide, two layers of non-transparent glazing paint.

Figure 3.18. Detail of railing post connection to bridge deck.

Figure 3.19. Section of railing post connection to bridge deck.

3.6.3 Moisture contents and rot propagation

M.C: Over FSP. in outer plank along both sides of the deck, Area with decay: Visible in outer plank along west side of the deck.

Figure 3.20. Decay in bridge deck, south-west corner.

3.6.4 Cause of the damage

Wood protection by design: Poor design with water leakage at the railing posts and several water traps. Maintenance: None Material: Spruce is used in the outer planks instead of a more durable material like treated pine.

3.7 Example 7 – Stressed laminated timber deck

3.7.1 Type of bridge and location

Built: 1998. Construction no: BatMan no: 2-1889-1, Svenska Träbroar (Martinsons) no: 5308/B Type: Pedestrian bridge, over road E4. Construction: Cable stayed with stress-laminated glulam deck. Age at inspection: 16 years Maintenance or reconstruction: No Location/coordinates RT90: Södertälje, Pershagen, X6560835, Y651361 Local climate: Over high way. Weather data: No

Figure 3.21.View from south.

3.7.2 Materials and dimensions

Deck planks: Spruce K30 ( Pica Abies). Dimension: 45-72 x 395mm. Surface treatment: One layer of primer with fungicide, two layers of non-transparent glazing paint.

Figure 3.22.Section of bridge deck with hole for drainage.

Figure 3.23.Detail of deck with connections for cross beam

3.7.3 Moisture contents and rot propagation

M.C: Over FSP. in outer planks along both sides of the deck. Over FSP. in the deck at crossbeams and drainage holes. Area with decay: Visible decay in outer planks along both sides of the deck.

Figure 3.24. High moisture content and decay in the area of the drain system in bridge deck.

Figure 3.25. Decay in the connecting area for a cross beam.

3.7.4 Cause of the damage

Wood protection by design: Poor design with water leakage at the railing posts and along both sides of the deck. Many water traps. Maintenance: None Material: Spruce is used in critical parts instead of a more durable material like treated pine.

3.8 Example 8 – Stressed laminated timber deck

3.8.1 Type of bridge and location

Built: 2007. Construction no: BatMan no: 22-470-1, Svenska Träbroar (Martinsons) no: 6020/A. Type: Road bridge over water, gravel road. Construction: Stress-laminated glulam deck. Age at inspection: 5 years Maintenance or reconstruction: No Location/coordinates RT90: Hädanberg, X7051859, Y657350 Local climate: Forest. Weather data: No

Figure 3.26. Bridge over Hädanbergån.

3.8.2 Materials and dimensions

Deck: Glulam L40, Spruce (Pica Abies). Dimension: 95 x 675mm. Surface treatment: One layer of primer with fungicide, two layers of non-transparent glazing paint.

Figure 3.27. Section of stress-laminated glulam deck with two levels of stressing rods.

3.8.3 Moisture contents and rot propagation

Table 3.1. Moisture content measured under the deck Measuring point Depth 5mm Depth 30mm North West corner 23 22 South West corner 23 20 North East corner 23 23 North East corner +0,5m 1a lamella 23 22 South East corner 23 22

Area with decay: None.

3.8.4 Cause of the damage

Figure 3.28.Uplift in every corner of the deck.

Moisture gradient in the deck: The moisture content in the glulam was about 12% when the bridge was constructed. The M.C. under the waterproof membrane is still around 12% but the M.C. in the underside of the deck is 23%. This gradient causes a cup/deformation of the deck Uplift: 5-10mm in all corners of the bridge deck, caused by the moisture gradient driven deformation,( cup) of the deck. Local climate: Condensation on the underside of the deck.

3.9 Example 9 – Stressed laminated timber deck

3.9.1 Type of bridge and location

Built: 2010. Construction no: BatMan no: 24-1932-1, Martinsons Träbroar AB no: 7196/D. Type: Pedestrian bridge over water. Construction: Stress-laminated glulam deck. Age at inspection: 3 years Maintenance or reconstruction: No Location/coordinates RT90: Umeå, X7091361, Y755429 Local climate: Open field. Weather data: No

Figure 3.29. Pedestrian bridge with a relatively thin stress-laminated deck and only one level of stressing rods.

3.9.2 Materials and dimensions

Deck: Glulam L40, Spruce ( Pica Abies). Dimension: 94,5 x 360mm. Surface treatment: One layer of primer with fungicide, two layers of non-transparent glazing paint.

Figure 3.30. Section of stress-laminated glulam deck with one level of stressing rods.

3.9.3 Moisture contents and rot propagation

Figure 3.31.Measuring points.

Table 3.2. Moisture content measured at the underside of the deck Measuring point Depth 0-45mm 1. 20 2. 21 3. 19 4. 20

Area with decay: None.

3.9.4 Cause of the damage

Figure 3.32. Uplift in every corner of the deck.

Moisture gradient in the deck: The moisture content in the glulam was about 12% when the bridge was constructed. The M.C. under the waterproof membrane is still around 12% but the underside of the deck has a M.C of 20%. This gradient causes a cup/deformation of the deck Uplift: 15-30mm in all corners of the bridge deck, caused by the moisture gradient driven deformation,( cup) of the deck. Local climate: Condensation on the underside of the deck.

Figure 3.33. Ice on the underside of the deck, due to condensation.

3.10 Example 10 – Stressed laminated timber deck

3.10.1 Type of bridge and location

Built: 2009. Construction no: BaTMan no: 2480-129-1, Martinsons Träbroar AB no: 7129/A. Type: Road bridge over water. Construction: Stress-laminated glulam deck. Age at inspection: 6 years Maintenance or reconstruction: No Location/coordinates RT90: Umeå, X7076671, Y766043 Local climate: Open, over water. Weather data: No

Figure 3.34. Road bridge with a stress-laminated deck with three levels of stressing rods.

3.10.2 Materials and dimensions

Deck: Glulam L40, Spruce ( Pica Abies) . Dimension: 219 x 810mm. Surface treatment: One layer of primer with fungicide, two layers of non-transparent glazing paint.

Figure 3.35. Section of stress-laminated glulam.

Figure 3.36. View of stress-laminated glulam deck with three levels of stressing rods.

3.10.3 Moisture contents and rot propagation

Table 3.3. Moisture content measured under the deck Measuring point Depth 5mm Depth 30mm North West corner 18 17 South West corner 18,5 17 North East corner 18 17 South East corner 17,5 17

Area with decay: None.

3.10.4 Cause of the damage

Figure 3.37. Slight uplift in two corners of the deck.

Moisture gradient in the deck: The moisture content in the glulam was about 12% when the bridge was constructed. The M.C. under the waterproof membrane is still around 12% but the underside of the deck has a M.C of 17%. This gradient causes a cup/deformation of the deck Uplift: 5-20mm in two corners of the bridge deck, caused by the moisture gradient driven deformation,( cup) of the deck. Local climate: Condensation on the underside of the deck.

Figure 3.38. Small amounts of water follows the railing posts but it does not effect the M.C in the deck.

3.11 Example 11 – Stressed laminated timber deck

3.11.1 Type of bridge and location

Built: 1994. Construction no: BaTMan no: 40-280-2, Svenska Träbroar AB no: 4254/A. Type: Road bridge over water. Construction: Stress-laminated deck. Age at inspection: 19 years Maintenance or reconstruction: No Location/coordinates RT90: Avan, X7147880, Y806204 Local climate: Shaded, over water. Weather data: No

Figure 3.39. Road bridge with a stress-laminated deck covered with a rubber membrane and deck planks.

3.11.2 Materials and dimensions

Deck planks: Treated pine ( Pinus Silvestris ), NTR class A. Stress-laminated deck: Spruce K30 ( Pica Abies) . Dimension: 72 x 420mm. Surface treatment: None

3.11.3 Moisture contents and rot propagation

Table 3.4. Moisture content measured under the deck Measuring point Depth 5mm Depth 30mm North West corner 17,8 17 South West corner 18,2 17 North East corner 18,6 17 South East corner 17,7 17

Area with decay: None.

Figure 3.40. No visible damages.

4 References

(1) Fjellström, Per-Anders, 2013-2015, selections from inspections for Swedish Transport Administration, municipalities and other bridge owners.

(2) Pousette, Anna, Fjellström, Per-Anders, Broinspektion – träbroar, SP Rapport 2004:41.

(3) Hauke Burkart, Statens Vegvesen, Trebrudetaljer, Erfaring fra inspeksjoner, drift og vedlikehold, Draft version 0.5, 9/6 ‐2014

(4) BaTMan, Bro och tunnel Management, Koder för inspektion av byggnadsverk, Del 1: Gemensamma koder, 2013-01-17, Vägverket.

Appendix A. Moisture measurements on timber truss bridges from Martinsons

A1. Timber truss bridges Moisture measurements were made by Martinsons during a few days in May 2009, so all the bridges were not measured on the same day. The measured moisture values represent the value of one day, and no trends of the moisture levels are shown. However the measurements may provide some information about where to expect the highest/lowest moisture contents in this type of bridges.

Martinsons Träbroar AB has built many timber truss bridges for pedestrians/cyclists. A follow-up of six truss bridges in middle and southern Sweden was made when the bridges were 8-12 years old; see location and description of bridges in Table A1 and Figure A1.

Today this type of bridge is designed with more protection against rain. In the studied bridges the bottom parts were unprotected and that was the reason for high moisture contents. Water runs down along the diagonals to the bottom chord. The measurements showed that the moisture levels could be too high and it meant that several parts of the bridge should protect in a better way. Today there are usually metal fittings on connection points on new truss bridges.

11 15 18 16

Figure A1. Map of Sweden with locations of bridges (5, 11, 14, 15, 16, 18)

Table A1. Description of bridges POS No. Name Built year Location Surface treatment. 5 5289 Södra länken 2001 Stockholm Oil 11 5165 Valabäcken Dösjebro 1999 Helsingborg OIl 14 5405 Högsby 2000 Högsby Oil 15 5013 Ronneby 1997 Ronneby Red paint 16 5305 Dösjebro 2000 Landskrona Red paint 18 5404 Kallinge 2000 Ronneby Red paint

Design life The design life of this type of bridge is usually 40 years in Sweden.

A2. Moisture measurements

Measurements Electric moisture meters measure the electric resistance in wood which varies with the moisture when the moisture content is less than 30 %. Moisture contents over this value up to 60 % were registered in some bridges, but these values are not actual moisture levels but mean the moisture contents are high and above fiber saturation point of the wood.

Measurement protocol Measurement points (1-12 as shown in Figure A2) were the same on all six bridges, to allow for comparisons.

The positions a, b, c and d refers to the various occurrences of the detail described, e.g. for measurement point 1 "Angle block bottom chord" all the angle blocks on the corresponding position at both bridge ends and both sides are separated with the above indexes as shown in the table below.

The orientation of the measuring points was registered, south, east, north, etc.

Moisture contents were measured at two levels from the wood surface, 10 mm and 40 mm.

Figure A2. Measuring points

Table A2. Protocol with measuring points Measuring Position Location point 1a Angle block, bottom chord Outside angle block 1b -”- -”- 1c -”- -”- 1d -”- -”- 2a Compression diagonal Outside diagonal 2b -”- -”- 2c -”- -”- 2d -”- -”-

3a Bottom chord Under angle block, Outside chord, High location -”- -”- -” - , Middle location -”- -”- -” - , Low location 3b Bottom chord Under angle block, Outside chord, High location -”- -”- -” - , Middle location -”- -”- -” - , Low location 4a Bottom chord At washer of tension rod 4b -”- -”- 4c -”- -”- 4d -”- -”- 5a Angle block, top chord Outside angle block 5b -”- -”- 5c -”- -”- 5d -”- -”- 6a Side strut Above cross beam 6b -”- -”- 6c -”- -”- 6d -”- -”- 7a Bracing Outside, Low location 7b -”- -”- 7c -”- -”- 7d -”- -”- 8a Cross beam At side strut, Top of beam -”- -”- -”- , Bottom of beam 8b Cross beam At side strut, Top of beam -”- -”- -”- , Bottom of beam 8c Cross beam At side strut, Top of beam -”- -”- -”- , Bottom of beam 8d Cross beam At side strut, Top of beam -”- -”- -”- , Bottom of beam 9a Cross beam At vertical member, Top of beam -”- -”- -”- , Bottom of beam 9b Cross beam At vertical member, Top of beam -”- -”- -”- , Bottom of beam 9c Cross beam At vertical member, Top of beam -”- -”- -”- , Bottom of beam 9d Cross beam At vertical member, Top of beam -”- -”- -”- , Bottom of beam 10a Cross beam At middle of beam, Top of beam, End of bridge 10a Cross beam At middle of beam, Bottom of beam, End of bridge 10b Cross beam At middle of beam, Top of beam, End of bridge -”- -”- At middle of beam, Bottom of beam, End of bridge 11a Support In bottom chord, At support 11b -”- -”- 11c -”- -”- 11d -”- -”- 12a Angle block of wind At support bracing 12b -”- -”- 12c -”- -”- 12d -”- -”-

A3. Results

Dörsjebro 5305-D

Figure A3. Description of bridge

Dörsjebro 5305-D (Built year: 2000) Surface treatment : Red paint Average moisture content : 24.8% (10mm: 24.3% 40mm: 25.2%) Wearing surface : Wood deck Surroundings : Somewhat leafy around the bridge (trees and bushes) Passage : Over river, high clearance Comment: Very high moisture contents in the angle block on bottom chord and in bottom chord around it. Very high moisture contents around the lower washers of tension rod.

Table A3. Average moisture content (%) in different directions South-East South-West North-East North-West 23.8 25.5 24.2 26.7

Figure A4. Moisture content (%) for all measuring points

Table A4. Measured moisture contents (%) at depths 10 mm and 40 mm Angle block, bottom chord 1a NE 1b SE 1c SW 1d NW 10 60.0 60.0 60.0 60.0 40 60.0 60.0 60.0 60.0 Compression diagonal 2a NE 2b SE 2c SW 2d NW 10 16.2 13.8 16.3 17.8 40 18.0 15.4 17.4 18.9 Bottom chord, under angle block, high 3a NE 3b SE 3c SW 3d NW 10 27.7 30.4 53.5 25.6 40 25.9 29.5 53.3 25.8 Bottom chord, under angle block, middle 3a NE 3b SE 3c SW 3d NW 10 26.7 27.5 28.5 26.9 40 28.5 29.1 30.3 27.0 Bottom chord, under angle block, low 3a NE 3b SE 3c SW 3d NW 10 25.0 25.5 25.8 22.0 40 26.8 25.8 26.5 23.9 Bottom chord, at 2nd washer of tension rod 4a NE 4b SE 4c SW 4d NW 10 26.8 24.8 23.7 60.0 40 29.8 33.8 25.7 60.0 Angle block, top chord 5a NE 5b SE 5c SW 5d NW 10 12.4 16.0 14.8 14.7 40 14.1 16.0 16.2 16.0 Side strut 6a NE 6b SE 6c SW 6d NW 10 18.4 16.2 18.8 20.2 40 18.3 16.8 19.0 21.6 Bracing 7a NE 7b SE 7c SW 7d NW 10 17.4 20.5 15.6 22.7 40 18.2 23.8 16.7 22.9 Cross beam at side strut, high 7a NE 7b SE 7c SW 7d NW 10 19.3 16.8 18.3 18.2 40 20.6 20.2 18.5 20.4 Cross beam at side strut, low 8a NE 8b SE 8c SW 8d NW 10 19.1 16.9 20.5 18.9 40 20.0 18.1 22.4 17.2 Cross beam at vertical member, high 9a NE 9b SE 9c SW 9d NW 10 21.7 15.2 16.0 18.3 40 22.4 16.2 16.7 19.0 Cross beam at vertical member, low 9a NE 9b SE 9c SW 9d NW 10 18.4 16.9 17.3 21.5 40 18.9 18.0 19.6 22.8 Cross beam at middle of bridge, high 10a E 10b W 10 23.3 22.2 40 22.0 22.1 Cross beam at middle of bridge, low 10a E 10b W 10 19.0 18.6 40 17.7 18.5 Angle block of wind bracing 11a NE 11b SE 11c SW 11d NW 10 24.7 21.5 21.0 23.0 40 21.5 22.8 22.8 23.0

Dörsjebro 5165-D

Figure A5. Description of bridge

Välabäcken 5165-D (Built year: 1999) Surface treatment : OIl Average moisture content: 26.7% (10mm: 26.7% 40mm: 27.2%) Wearing surface: Wood deck, with dense mat on deck Surroundings : Very leafy around the bridge (trees and bushes) Passage : Over river, high clearance Comment: Very high moisture contents in the angle block on bottom chord. Very high moisture contents around the lower washers of tension rod.

Table A5. Average moisture content (%) in different directions South-East South-West North-East North-West 25.3 32.8 24.1 23.1

Figure A6. Moisture content (%) for all measuring points

Table A6. Measured moisture contents (%) at depths 10 mm and 40 mm Angle block, bottom chord 1a NW 1b NE 1c SW 1d SE 10 23.0 29.4 60.0 29.3 40 25.0 30.6 60.0 31.5 Compression diagonal 2a NW 2b NE 2c SW 2d SE 10 14.7 30.5 19.3 17.9 40 15.6 30.0 19.5 19.0 Bottom chord, under angle block, high 3a NW 3b NE 3c SW 3d SE 10 22.4 25.1 60.0 30.3 40 24.1 25.5 43.5 30.3 Bottom chord, under angle block, middle 3a NW 3b NE 3c SW 3d SE 10 21.2 24.5 60.0 22.6 40 21.7 24.8 60.0 21.0 Bottom chord, under angle block, low 3a NW 3b NE 3c SW 3d SE 10 27.7 25.2 34.7 23.6 40 26.6 23.4 29.7 22.3 Bottom chord, at 2nd washer of tension rod 4a NW 4b NE 4c SW 4d SE 10 60.0 42.4 47.2 40.7 40 60.0 60.0 60.0 60.0 Angle block, top chord 5a NW 5b NE 5c SW 5d SE 10 14.1 14.7 14.3 15.8 40 14.2 14.3 14.6 15.4 Side strut 6a NW 6b NE 6c SW 6d SE 10 17.3 16.0 18.4 17.7 40 17.7 15.9 18.3 18.1 Bracing 7a NW 7b NE 7c SW 7d SE 10 14.2 18.6 19.2 17.1 40 17.6 19.5 21.7 20.1 Cross beam at side strut, high 7a NW 7b NE 7c SW 7d SE 10 14.1 24.5 17.8 17.3 40 15.0 21.0 17.7 17.3 Cross beam at side strut, low 8a NW 8b NE 8c SW 8d SE 10 13.6 14.8 17.4 16.7 40 14.5 15.1 18.4 16.7 average 14.1 15.0 17.9 16.7 Cross beam at vertical member, high 9a NW 9b NE 9c SW 9d SE 10 15.7 16.9 24.0 21.1 40 16.1 16.5 23.5 20.4 Cross beam at vertical member, low 9a NW 9b NE 9c SW 9d SE 10 16.4 21.1 20.0 28.0 40 16.9 22.7 18.7 28.5 Cross beam at middle of beam, high 10a N 10b N 10 37.0 49.0 40 31.0 45.0 Cross beam at middle of beam, low 10a S 10b S 10 23.4 23.8 40 21.4 19.0 Angle block of wind bracing 11a NW 11b NE 11c SW 11d SE 10 36.0 25.6 41.7 41.5 40 51.5 27.4 58.9 48.6

Ronneby 5013-D

Figure A7. Description of bridge

Ronneby 5013-D (Built year: 1997) Surface treatment : Red Average moisture content :: 24.6% (10mm: 23.6% 40mm: 25.5%) Wearing surface : Wood deck Surroundings : Open country Passage : Over river, low clearance Comment: Very high moisture contents in the angle block on bottom chord. Very high moisture contents around the lower washers of tension rod. Gravel on bottom chord and angle block.

Table A7. Average moisture content (%) in different directions South-East South-West North-East North-West 23.8 23.2 24.2 28.0

Figure A8. Moisture content (%) for all measuring points

Table A8. Measured moisture contents (%) at depths 10 mm and 40 mm Angle block, bottom chord 1a SW 1b NW 1c SE 1d NE 10 30.2 50.0 35.0 29.0 40 30.2 60.0 46.0 32.5 Compression diagonal 2a SW 2b NW 2c SE 2d NE 10 20.7 22.4 17.3 24.1 40 21.7 22.0 20.0 25.2 Bottom chord, under angle block, high 3a SW 3b NW 3c SE 3d NE 10 22.0 21.9 21.7 21.8 40 23.6 23.8 22.6 23.7 Bottom chord, under angle block, middle 3a SW 3b NW 3c SE 3d NE 10 29.6 24.8 25.7 22.2 40 31.4 26.8 27.6 24.0 Bottom chord, under angle block, low 3a SW 3b NW 3c SE 3d NE 10 19.3 20.5 21.6 18.8 40 20.8 23.0 22.5 18.8 Bottom chord, at 2nd washer of tension rod 4a SW 4b NW 4c SE 4d NE 10 35.7 60.0 49.6 60.0 40 60.0 60.0 60.0 60.0 Angle block, top chord 5a SW 5b NW 5c SE 5d NE 10 17.4 13.8 16.4 16.2 40 18.0 14.0 16.0 17.2 Side strut 6a SW 6b NW 6c SE 6d NE 10 20.7 22.9 16.8 17.9 40 22.0 24.3 17.6 19.2 Bracing 7a SW 7b NW 7c SE 7d NE 10 16.8 21.0 18.6 19.3 40 18.9 22.3 19.0 19.5 Cross beam at side strut, high 7a SW 7b NW 7c SE 7d NE 10 17.2 22.3 16.8 18.2 40 18.4 24.0 17.6 19.1 Cross beam at side strut, low 8a SW 8b NW 8c SE 8d NE 10 18.7 23.7 16.9 17.2 40 20.7 25.2 17.7 18.3 Cross beam at vertical member, high 9a SW 9b NW 9c SE 9d NE 10 15.8 23.6 18.2 18.3 40 17.6 23.7 18.9 18.7 Cross beam at vertical member, low 9a SW 9b NW 9c SE 9d NE 10 18.2 25.5 17.3 19.9 40 20.0 26.0 18.8 20.5 Cross beam at middle of bridge, high 10a W 10b W 10 24.8 21.1 40 25.5 20.4 Cross beam at middle of bridge, low 10a E 10b E 10 21.8 17.8 40 21.3 17.8 Angle block of wind bracing 11a SW 11b NW 11c SE 11d NE 10 22.2 28.4 24.0 29.3 40 23.0 29.4 26.0 29.1

Kallinge 5404-D

Figure A9. Description of bridge

Kallinge 5404-D (Built year: 2000) Surface treatment : Red Average moisture content : 22.1% (10mm: 21.2% 40mm: 22.9%) Wearing surface : Wood deck Surroundings : Somewhat leafy around the bridge (trees and bushes) Passage : Over river, high clearance Comment: Very high moisture contents in the angle block on bottom chord. Very high moisture contents around the lower washers of tension rod

Table A9. Average moisture content (%) in different directions South West North East 21.5 21.4 21.2 25.3

Figure A10. Moisture content (%) for all measuring points

Table A10. Measured moisture contents (%) at depths 10 mm and 40 mm Angle block, bottom chord 1a E 1b S 1c W 1d N 10 60.0 27.5 28.1 31.0 40 60.0 31.4 31.2 36.7 Compression diagonal

2a E 2b S 2c W 2d N

10 20.0 16.6 17.9 16.7 40 20.7 17.4 17.9 16.8 Bottom chord, under angle block, high 3a E 3b S 3c W 3d N 10 20.0 16.6 17.9 16.7 40 20.7 17.4 17.9 16.8 Bottom chord, under angle block, middle 3a E 3b S 3c W 3d N 10 23.8 26.3 23.1 25.1 40 25.0 28.2 24.0 26.5 Bottom chord, under angle block, low 3a E 3b S 3c W 3d N 10 25.8 24.3 23.1 34.9 40 27.4 25.2 23.1 35.7 Bottom chord, at 2nd washer of tension rod 4a E 4b S 4c W 4d N 10 40.0 27.0 39.0 22.0 40 57.9 30.9 45.0 28.0 Angle block, top chord 5a E 5b S 5c W 5d N 10 16.7 16.0 17.0 15.0 40 18.0 17.4 18.0 17.0 Side strut 6a E 6b S 6c W 6d N 10 21.6 21.0 17.9 15.9 40 22.3 22.7 19.8 18.0 Bracing 7a E 7b S 7c W 7d N 10 15.7 16.7 15.8 40 17.8 17.3 15.6 Cross beam at side strut, high 7a E 7b S 7c W 7d N 10 17.4 18.4 13.6 14.3 40 18.4 18.7 15.6 15.0 Cross beam at side strut, low 8a E 8b S 8c W 8d N 10 16.2 19.6 17.4 14.9 40 17.2 20.4 18.9 17.1 Cross beam at vertical member, high 9a E 9b S 9c W 9d N 10 18.0 17.0 15.3 15.3 40 19.4 18.5 16.0 16.2 Cross beam at vertical member, low 9a E 9b S 9c W 9d N 10 23.5 20.4 19.3 17.8 40 24.3 20.9 21.1 20.1 Cross beam at middle of bridge, high 10a SE 10b SE 10 21.0 17.0 40 23.1 17.6 Cross beam at middle of bridge, low 10a NW 10b NW 10 16.0 15.3 40 16.2 15.7 Angle block of wind bracing 11a E 11b S 11c W 11d N 10 19.6 24.3 24.1 24.6 40 21.4 24.2 24.7 24.2

Mönsterås A-002 (Södra Länken 5289)

Figure A11. Description of bridge

Mönsterås A-002 (fd Södra Länken 5289) (Built year: 2000) Surface treatment : Oil Average moisture content : 17.0% (10mm: 16.2% 40mm: 17.7%) Wearing surface : Wood deck Surroundings : Open (no bushes etc.) Passage : Over river, low clearance Comment: Very high moisture contents in the angle block on bottom chord. Very high moisture contents around the lower washers of tension rod

Table A11. Average moisture content (%) in different directions South-East South-West North-East North-West 16.2 16.8 16.2 18.8

Figure A12. Moisture content (%) for all measuring points

Table A12. Measured moisture contents (%) at depths 10 mm and 40 mm Angle block, bottom chord 1a SE 1b SW 1c NE 1d NW 10 17,0 21,5 15,5 22,2 40 18,0 21,3 16,5 25,8 Compression diagonal 2a SE 2b SW 2c NE 2d NW 10 15,6 15,5 14,7 14,3 40 16,9 17,0 17,3 15,5 Bottom chord, under angle block, high 3a SE 3b SW 3c NE 3d NW 10 14,7 17,9 17,1 24,8 40 20,1 17,0 18,6 24,8 Bottom chord, under angle block, middle 3a SE 3b SW 3c NE 3d NW 10 18,5 18,2 18,1 18,6 40 20,0 19,3 18,9 19,3 Bottom chord, under angle block, low 3a SE 3b SW 3c NE 3d NW 10 16,8 16,5 16,1 21,0 40 18,5 18,0 16,9 22,7 Bottom chord, at 2nd washer of tension rod 4a SE 4b SW 4c NE 4d NW 10 19,3 19,0 19,7 18,0 40 23,2 22,3 22,0 23,4 Angle block, top chord 5a SE 5b SW 5c NE 5d NW 10 13,0 12,8 11,6 13,2 40 14,4 13,6 13,6 14,1 Side strut 6a SE 6b SW 6c NE 6d NW 10 13,0 15,2 12,1 13,0 40 15,0 16,3 14,8 14,6 Bracing 7a SE 7b SW 7c NE 7d NW 10 12,0 14,0 14,2 40 13,2 15,2 15,6 Cross beam at side strut, high 7a SE 7b SW 7c NE 7d NW 10 13,5 14,1 13,8 18,1 40 17,5 14,6 15,5 19,9 Cross beam at side strut, low 8a SE 8b SW 8c NE 8d NW 10 13,8 15,0 13,7 14,0 40 14,0 15,3 14,0 15,1 Cross beam at vertical member, high 9a SE 9b SW 9c NE 9d NW 10 14,6 14,5 15,2 21,2 40 15,8 16,2 16,6 21,5 Cross beam at vertical member, low 9a SE 9b SW 9c NE 9d NW 10 13,8 16,3 17,3 16,9 40 15,1 17,4 19,1 18,2 Cross beam at middle of bridge, high 10a S 10b S 10 40 Cross beam at middle of bridge, low 10a N 10b N 10 40 Angle block of wind bracing 11a SE 11b SW 11c NE 11d NW 10 17,6 17,4 17,2 18,8 40 18,7 18,5 18,6 18,5

5405-D Högsby

Figure A13. Description of bridge

Högsby 5405-D (Built year: 2000) Surface treatment : Oil Average moisture content : 16% (10mm: 15,12% 40mm: 17,0%) Wearing surface : Wood deck Surroundings : Open country Passage : Over river, high clearance Comment: Very low moisture contents. Cracks on inside of upper chord.

Table A13. Average moisture content (%) in different directions South-East South-West North-East North-West 14.9 15.3 15.4 17.8

Figure A14. Moisture content (%) for all measuring points

Table A14. Measured moisture contents (%) at depths 10 mm and 40 mm Angle block, bottom chord 1a SW 1b NW 1c SE 1d NE 10 14,1 20,5 15,8 17,6 40 21,0 25,5 20,2 20,8 Compression diagonal 2a SW 2b NW 2c SE 2d NE 10 11,3 15,0 11,7 13,8 40 14,1 16,8 13,7 15,7 Bottom chord, under angle block, high 3a SW 3b NW 3c SE 3d NE 10 14,0 15,4 14,9 14,8 40 14,0 15,8 15,4 15,8 Bottom chord, under angle block, middle 3a SW 3b NW 3c SE 3d NE 10 17,5 16,2 17,4 16,0 40 18,8 16,9 18,9 17,8 Bottom chord, under angle block, low 3a SW 3b NW 3c SE 3d NE 10 17,8 16,7 16,8 16,8 40 18,6 18,0 17,8 19,2 Bottom chord, at 2nd washer of tension rod 4a SW 4b NW 4c SE 4d NE 10 16,9 22,5 40 23,7 47,0 Angle block, top chord 5a SW 5b NW 5c SE 5d NE 10 13,2 10,6 12,2 12,0 40 13,9 13,4 13,8 12,7 Side strut 6a SW 6b NW 6c SE 6d NE 10 12,5 15,9 11,2 12,4 40 13,4 16,2 13,3 14,5

Bracing 7a SW 7b NW 7c SE 7d NE 10 11,5 14,7 40 13,4 16,2 Cross beam at side strut, high 7a SW 7b NW 7c SE 7d NE 10 12,5 15,8 12,6 12,8 40 13,7 16,7 13,2 13,8 Cross beam at side strut, low 8a SW 8b NW 8c SE 8d NE 10 12,8 14,4 12,5 13,7 40 13,9 15,3 14,4 15,2 Cross beam at vertical member, high 9a SW 9b NW 9c SE 9d NE 10 12,3 15,4 13,3 13,2 40 14,2 16,0 14,4 14,2 Cross beam at vertical member, low 9a SW 9b NW 9c SE 9d NE 10 13,0 15,0 14,9 15,2 40 14,8 16,7 15,1 17,5 Cross beam at middle of bridge, high 10a W 10b W 10 20,4 18,4 40 19,3 18,9 Cross beam at middle of bridge, low 10a E 10b E 10 18,7 15,3 40 17,1 15,4 Angle block of wind bracing 11a SW 11b NW 11c SE 11d NE 10 19,2 18,5 17,5 17,3 40 21,1 20,0 17,5 17,9

Comparison of the moisture contents of the bridges

Dörsjebro 5305-D (Röd)

50 10 40 40 30 20 10 1a 1c 2a 2c 3a 3c 3a 3c 3a 3c 4a 4c 5a 5c 6a 6c 7a 7c 7a 7c 8a 8c 9a 9c 9a 9 c 10 a 10 a 11a 11c

Ronneby 5013-D (Röd)

60,0

50,0

40,0 10

30,0

20,0

10,0 1a 1b 1c 1d 2a 2b 2c 2d 3a 3b 3c 3d 3a 3b 3c 3d 3a 3b 3c 3d 4a 4b 4c 4d 5a 5b 5c 5d 6a 6b 6c 6d 7a 7b 7c 7d 7a 7b 7c 7d 8a 8b 8c 8d 9a 9b 9c 9d 9a 9b 9c 9d 10a 10b 10a 10b 11a 11b 11c 11d Kallinge 5404-D (Röd)

60, 0

50, 0

40, 0 10

30, 0

20, 0

10, 0 1a 1b 1c 1d 2a 2b 2c 2d 3a 3b 3c 3d 3a 3b 3c 3d 3a 3b 3c 3d 4a 4b 4c 4d 5a 5b 5c 5d 6a 6b 6c 6d 7a 7b 7c 7d 7a 7b 7c 7d 8a 8b 8c 8d 9a 9b 9c 9d 9a 9b 9c 9d 10a 10b 10a 10b 11a 11b 11c 11d

Dörsjebro 5165-D (Oljad) Cross Wind angle 60,0 beam block

50,0

40,0 10

30,0

20,0

10,0 1a 1b 1c 1d 2a 2b 2c 2d 3a 3b 3c 3d 3a 3b 3c 3d 3a 3b 3c 3d 4a 4b 4c 4d 5a 5b 5c 5d 6a 6b 6c 6d 7a 7b 7c 7d 7a 7b 7c 7d 8a 8b 8c 8d 9a 9b 9c 9d 9a 9b 9c 9d 10a 10b 10a 10b 11a 11b 11c 11d

Bottom MönsteråsRod A-002 (Södra Länken 5289) (Oljad) Angle 60, 0 Chord washer block 50, 0

40, 0 10

40 30, 0

20, 0

10, 0

1a 1b 1c 1d 2a 2b 2c 2d 3a 3b 3c 3d 3a 3b 3c 3d 3a 3b 3c 3d 4a 4b 4c 4d 5a 5b 5c 5d 6a 6b 6c 6d 7a 7b 7c 7d 7a 7b 7c 7d 8a 8b 8c 8d 9a 9b 9c 9d 9a 9b 9c 9d 10a 10b 10a 10b 11a 11b 11c 11d

5405-D Högsby (Oljad)

60,0

50,0

40,0

40 30,0

20,0

10,0

1a 1b 1c 1d 2a 2b 2c 2d 3a 3b 3c 3d 3a 3b 3c 3d 3a 3b 3c 3d 4a 4b 4c 4d 5a 5b 5c 5d 6a 6b 6c 6d 7a 7b 7c 7d 7a 7b 7c 7d 8a 8b 8c 8d 9a 9b 9c 9d 9a 9b 9c 9d 10a 10b 10a 10b 11a 11b 11c 11d

1 2 3 4 5 6 7 8 9 10 11

SP Technical Research Institute of Sweden Our work is concentrated on innovation and the development of value-adding technology. Using Sweden's most extensive and advanced resources for technical evaluation, measurement technology, research and development, we make an important contribution to the competitiveness and sustainable development of industry. Research is carried out in close conjunction with universities and institutes of technology, to the benefit of a customer base of about 10000 organisations, ranging from start-up companies developing new technologies or new ideas to international groups.

SP Sveriges Tekniska Forskningsinstitut Box 857, 501 15 BORÅS SP Rapport 2015:XX Telefon: 010-516 50 00, Telefax: 033-13 55 02 ISBN XXXX-XX E-post: [email protected], Internet: www.sp.se ISSN 0284-5172 www.sp.se

Mer information om SP:s publikationer: www.sp.se/publ