Structural Analysis of Historical Constructions - Modena, Lourenço & Roca (eds) © 2005 Taylor & Francis Group, London, ISBN 04 15363799 Library of Parliament of Canada - conservation, rehabilitation, upgrade case study presentation M. Petrescu-Comnene Adjeleian Allen Rubeli Limited, Consulting Structural Engineers, Ottawa, Toronto S.R. Higgins Spencer R. Higgins Architect In c., Toronto ABSTRACT: The Library of the Parliament of Canada is considered to be the premier heritage building in Canada, and the only surviving building ofthe original high-Victorian parliamentary building built in the 1860's. The building continues to serve its original function as the Parliamentary Library for both the Senate and House of Commons. In 1998, a Consultant Team was retained by Public Works and Government Services Canada to design and oversee a project to conserve, rehabilitate and upgrade the building for a design life span of50 years. The conservation aspect includes an extensive list of structural and architectural elements. The first part of the presentation will address the specific topic of stone masonry rehabilitation and conservation, with an emphasis on issues related to northern climates, i.e. water penetration and freeze- thaw cycling. The second part, will present some structural interventions addressing upgrading of the building to current code requirements and modern environmental control specific to libraries and archives housing valuable historical docllments. TNTRODUCTION 1.1 History oflhe LibrO/y of Parliament The Library of Parliament (Fig. I) was originally constrllcted in the 1860's and extensively rebuilt in 1952- 56, following a fire. It is the single remain­ ing original building on Parliament Hill housing the Parliament of Canada. The Library was bllilt to the designs of Fuller and Jones in the form of an English Gothic chapter house, and decorated in an exuberant Victorian manner. It is the premier heritage building in Canada, located on a rugged promontory, high over the Ottawa River. It is linked to the Centre Block (hollsing the Senate and the House of Commons), which was rebllilt in its entirety afier a devastating fire in 1916. Its image is reproduced on Canadian postage stamps and banknotes. Construction of the Library along with the Pari ia­ ment Buildings began in December 1859. In June 1866 the Parliament opened its first session in the new build­ ing, however the Library masonry walls were only constructed to a height of 13 m. A temporary roofwas installed over the ring walls. Construction ofthe stone masonry walls restarted in 1871, however the ma in roof structure design was changed from a masonry dome to a wrought iron truss system designed and Figure I. Library of Parliament, c 1875 (NAC, C-I 000 I). 1273 built by Thomas Fairbairn Engin eering Company Ltd., of Manchester, England. The Library moved into the new building in October 1876. In 1888, a cyclone blew away large sections of the original slate roof, and the roofing was replaced with copper. In 19 16 the Centre Block was destroyed by fire, but the Library bui lding suffered only minor damage, being saved by a iron fire door. However, the luck ran out in 1952, when a fire started in the dome of the Library causing significaRt damage to the roof struc­ ture and extensive water damage to the collections. Mathers and Haldenby Architects of Toronto were retained to prepare plans and specifications for the rehabilitation, repair and fireproofing of the Library. While the exterior appearance of the building was retained, the interior layout and fea tures suffered sig­ nificant alteration. It was then that the origin al Reading Figure 2. Interi or of Library ofParli ament, photography by Room brick vaulted floor was removed and replaced Williams J. Topley, c.1898 (NAC, PA-8375). by two leveis (basement and sub-basement) of book stacks; a large number ofbags of cement were used for walls also provi de the resistance for lateralloads, i.e. the grouting of buttresses; sanded grout was inj ected wind and earthquake. The walls are founded on large into footings; joints were re-pointed with cement­ slabs of limestone positioned on limestone bedrock. gauged lime mortar; brick lining walls on the inside The bedrock has significant jointing with variable face of the outer ring wall were removed and replaced directions and angles. with cast-in-place concrete; and the secondary tim­ The ring walls are of random rubble construction ber roof framing was replaced by steel members. The built to courses with plain ashlarquoins. The outer face Library was re-opened in June 1956. ofthe wa ll was squared and bedded in mortar, and the Between 1956 and 1998 the Library benefited from inner face was built up of coursed random rubble work small maintenance and upgrading projects address­ grouted up in lifts as the work progressed. The outer ing lighting problems, heating and air conditioning, ring wall is 1200 mm th ick at its base, and reduces to and fi t-up of a rare-book storage room. A number 850 mm above the main floor. The inner ring wall is of studies were completed regarding water infiltra­ 1500 mm thick below the main floor, and reduces to tion, high humidity leveIs, and the condition of the 1300 mm for the upper secti on. According to the orig­ masonry walls. In June 1998, Public Works and Gov­ inai specifications, keystones were placed on a regu lar ernrnent Services Canada retained an Architect Joint pattern to connect the face wythe to the rubble core. Venture Firm as the architects for the Conservation, However, the investigation conducted by the design Rehabilitation and Upgrade Project for the Library of team could not clearly identify the keystones. Parliament. The Joint Venture retained the engineer­ The area inside the inner ring wall is referred to as ing sub-consultants, as well as specialty consultants. the Reading Room. Originally, it had only one base­ Construction documents were completed in May 200 I. ment levei, with the reading room rising approximately Construction started in March 2002, and is expected 30 m to the base of the lantern, and up to 4 I m at to be completed in 2005. the lantem. The on ly floor slab had a brick arch sup­ port, with a concrete, graveI, sand and hydraulic lime morta r topping. The slab was carrying the multi- leveI 1.2 Structural description wooden book stacks (Fig. 2), with eight radial pro­ The main vertical structural elements of the Library jecting stacks, and access from the perimeter offices are the two concentric masonry wa ll s: the outer ring area. The stacks have a wrought iron framing, and wall and the inner ring wall (Fig. 4). The diameter include two leveIs of circulation galleries to provi de of the inner ring wall is 26.5 m, while the diame­ access to the shelves and projecting stacks. During ter of the outer ring wall is 45 m. The outer ring the renovations of 1950's, the reading room slab was wall is stiffened by 16 buttresses, with flying but­ removed and replaced with a 127 mm two way re in­ tresses arching over to the inner ring wal l. The inner forced concrete slab supported on steel columns on ring wall provides the support for the arched wrought a 2743 mm grid. At the same time, the single base­ iron truss system supporting the main roof and the ment levei was replaced with two leveis, by sli ghtly lantern. At its lower leveIs, together with the outer 10wering the bedrock and reducing the clear height on ring wall they provide the support fo r the perime­ each leveI. The steel columns, built up from angles and ter offices slabs (five leveis) and the lower roof. The tee sections, were integrated with the mobile shelvin g 1274 MAIN FLOOR PLAN Figure 4. Main Floor Plan. framing and steel deck system. At the same time, the original timber lean-to roof over the perimeter offices Figure 3. Library of Parliament - Cross section. was replaced with a steel framed roof and steel deck. The original timber Lantem structure was com­ system. The shellacked pine book stacks, refurbished pletely replaced during the 1953 renovations. A new off-site, were reinstalled on the newly constructed slab. structural steel framing system was installecl, spring­ The perimeter offices area provides office and ing from the compression ring truss. lts structure service space, including four stairs on a diagonally includes cranked steel columns, two leveis of hori­ opposite configuration. The northeast stair is the Stair zontal diaphragm framing, secondary steel framing, Tower, which extends to the top ofthe inner ring wall, and the central pipe column for the wrought-iron and provides the access to the roof and lantem. It weathervane. contains a stone circular stair within a round stone The Library also includes a number of architectural masonry tower. Ali the perimeter offices slabs were features - pinnacles, stairtower, and chimney. Stability reconstructed in 1953, with a 65 mm reinforced con­ ofthese masonry elements was addressed by the struc­ crete floor slab, supported either by a reinforced tural team, and the designers provided the reinforcing concrete skin wall placed against the ring walls, or details. horizontal slots cut into the stone masonry walls. The roof over the Reading Room is carried by 1.3 Struclural challengesfor building upgrade a semi-circular wrought-iron truss system, which is composed of 16 long trusses alternating with 16 short The current conservation, rehabilitation and upgrade trusses (Fig. 3). Ali the trusses are connected at the top project scope-of-work listed a number ofrequirements to a wrought-iron ring compression truss, and are sup­ set up by the Client.