Roof Truss Research Articles

Stability Analysis on the Structureof a Multipurpose Gymnasium

This study focused on the structure of a multipurpose university gymnasium. The lower part of the structure is reinforced concrete frame structure and the top is steel roof truss, and the roof use radiation truss brace shell structure. In this paper, buckling analysis of the separate steel roof and the overall structure are investigated under the basic or combined load cases, and the stability of the structure is verified. This study provides a valuable reference for the design of similar structures.

High School Gymnasium Roof Truss Support Collapse

Roof truss supports from a high school gymnasium were evaluated after the roof collapsed under a heavy load of snow. The roof collapsed when the truss supports buckled. Three significant structural deficiencies were identified during the evaluation: (1) Truss supports were not gusseted, allowing for side-to-side movement. (2) Yield strength of the support was 9% below the minimum specified yield strength specified for the base material, ASTM A36. (3) Full penetration was not achieved on the butt weld between the truss and support.

Compression Test on Cold-Formed Steel Built-Up Back-to-Back Channels Stub Columns

Built-up sections are used to resist load induced in a structure when a single section is not sufficient to carry the design load for example roof trusses. In current North American Specification, the provision has been substantially taken from research in hot-rolled built-up members connected with bolts or welds [1]. The aim of this paper is to investigate on built-up back-to-back channels stub columns experimentally and theoretically using Effective Width Method and Direct Strength Method. Compression test was performed on 5 lipped channel and 5 back-to-back channels stub columns fabricated from cold-formed steel sheets of 1.2mm thicknesses. The test results indicated that local buckling is the dominant failure modes of stub columns. Therefore, Effective Width Method predicts the capacity of stub columns compared to Direct Strength Method. When compared to the average test results, results based on EWM are 5% higher while results based on DSM are 12% higher for stub column.

Steel City Sharp

Pittsburgh’s new ice hockey arena, the Consol Energy Center, is the first in the National Hockey League to achieve gold certification in the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) program. The formidable site and engineering challenges its designers faced ranged from a drastically sloping site and pronounced variations in geological characteristics to a 100 ft tall atrium space, a 400 ft long S-shaped curtain wall, and soaring and elegant roof trusses. The result is a stunning 720,000 sq ft venue for the Steel City that is not only modern but every bit as sharp as the blades that cut across its signature ice sheet.

A STUDY ON THE TIMBER FRAMEWORK OF CHURCHES IN THE NORTHERN VIETNAM, BUI CHU, THAI BINH, AND PHAT DIEM DIOCESES

Our surveys have revealed that 1,224 churches are located in three dioceses in the northern region of Vietnam and that 298 churches of them are timber-framed churches. These timber-framed churches are constructed with Vietnamese traditional methods. In this paper, based on the information obtained from our surveys, we divided the structures of the timber-framed churches into frameworks composed of columns/beams and roof trusses, and then classified each of them individually. By paying attention to the beam laid on the central columns, the framework was divided largely into two categories and further classified into six smaller categories according to the beams laid on the outer columns. The roof truss was divided into five categories based on the shape and composition of members used. From the correlation between the two factors, in the end we categorized them into five structural types, and summarized the characteristics and transition of the structures of the timber-framed churches.

STUDY ON ULTIMATE LIMIT OF STEEL ROOF TRUSS AT NUCLEAR POWER PLANT

In the seismic safety evaluation of the nuclear power plant, the reasonable specification of the limit performance is required.The purpose of this study is to clarify the limit performance of large span roof truss at nuclear power plant, for advanced evaluations. First, in this study, the static loading test of large-scale specimens, that imitate real roof truss, is done. Then, behavior and deformation capacity of roof truss in large deformation area are examined. And by analytical method, the correspondence of the damage of truss member and whole behavior is confirmed. In addition, a useful evaluation method of ultimate limit of roof truss is proposed, and the validity of proposed method is confirmed by the test evaluations of some roof truss models.

Building Construction in North Cyprus: Problems and Alternatives Solutions

In recent years the number of medium rise buildings is slowly increasing in North Cyprus. As a result, the need to use new construction materials and technologies is becoming more essential. Using hot rolled steel and cold rolled galvanized light gauge steel for building frames are two of the possible alternatives to reinforced concrete building frames currently used in the market. The number of steel framed buildings so far is less than five percent of all the buildings. Steel is an imported material. It is mainly used for the industrial buildings, either as truss roof system and/or complete portal frame and/or truss roof steel framed single storey structures. The engineers are not knowledgeable enough, the lack of training, inadequate fabrication facilities and many years of having used to reinforced concrete framed structures are the main reasons for engineers not using enough steel framed structures. The first part of this paper investigates the problems and possible solution of steel usage for structures in North Cyprus by analysing the number of buildings constructed after the year 2000. The second part summarizes the problems relating to the local reinforced concrete framed building construction, including inadequacies of repair, quality control, material quality and isolation of buildings from the external effects. Sustainability, stability and repair aspects for steel structures in comparison to reinforced concrete structures in North Cyprus are also briefly discussed in this paper.

WOODEN ROOF TRUSS IN WAR DAMAGE RECONSTRUCTION OF TOKYO STATION

On our site, I investigated wooden roof truss of Tokyo station that were built at war damage reconstruction. It became clear that the wooden roof truss is ‘Modern wood truss’ studied and developed in 1930-1945 age before and during World War II. In this paper, the form materials and the joining method of the wooden roof truss are made clear. In addition, it was clear about engineer who was concerned the wooden roof truss construction of Tokyo station.

The Savoy Hotel enhancement Part II: the dome

AbstractThe Savoy is London’s landmark hotel located on the Thames Embankment between Waterloo Bridge and Westminster. It was closed in December 2007 for a complete refurbishment and will reopen soon.One major part of the refurbishment — the underpinning of the existing cantilevering lattice trusses, from which the south façade is suspended — was published in ”The Savoy Hotel enhancement part I: south façade” in the 2/2010 issue of this journal. Other key parts of the refurbishment are the installation of a new lift above Savoy Way, including extending the lifts up to the 8th floor, and the installation of a large ornate glass dome above the hotel’s ”Thames Foyer”. To incorporate the dome, the existing pitched truss roof had to be temporarily supported, the tension member had to be severed and a new box structure, supporting the huge glass ornate dome, had to be inserted. The structural work undertaken is described here.

Stability Analysis on the Roof Trusses of the Broumov Group of Churches to Underline Statical Sense of Dientzenhofers

The Broumov group of churches represents an integral part of Bohemian baroque architecture. The famous Dientzenhofer family of architects, that helped define the Bohemian baroque style in the early 18th century, designed the Broumov group for the governing Benedictine abbey of St. Wenceslaw in Broumov. This report summarizes a structural investigation, using FIN10 finite element software, into the stability and efficiency of the roof trusses design. The structures age and current state were taken into account in calculating both the applied loads and structural capacity by increasing loads and reducing material strength. A damage analysis, including identification of fungi species, was performed, documented and implemented in a three-dimensional model for comparison with undamaged results. Magnitude and distribution of axial and bending forces were determined using both two dimensional and three-dimensional models for several load cases. Using the comparison of 1st order and 2nd order structural analysis results and Eurocode specified criteria, critical and unnecessary members of the roof system were identified and evaluated. Classical linear elastic 2nd order theory was used based of Eulerian principles, ignoring geometrical non-linearity and non-linear material effects. The main analysis was performed on the St. Ann church in Viznov and St. Barbora church in Otovice.

Revitalization of Historical Building in Wrocław’s City Centre, Poland

Some aspects of the revitalization of the 14th century historical building are presented in the paper. The building was originally used as a poorhouse and a hospital for children. The original Gothic masonry building on the site was a two-storey building with a cellar, situated in a corner of two streets. In the middle of the 19th century the building was converted into a school and then the first large-scale demolition of the hospital’s Gothic walls took place. After the 2nd World War a school was also situated in the building, where it existed until the late nineties. The aim of the renovation process was to convert it into an exclusive office block. The design works were preceded by historical research and on-site investigations. Complex conversion of the object consisted in the reconstruction of the old building structure, creating the inner courtyard and covering it with a glass roof. In the existing part of the basement one of the longest single-nave vaults in Poland and the exquisite roof truss system with a lying bidding-rafter post deserved special attention during the renovation.

A Study on a behavior of a gabled roof truss structure with VED installed in truss chords

A Study on a behavior of a gabled roof truss structure with VED installed in truss chords

Repair of Wood Trusses Loaded in Tension with Adhesively Bonded Carbon-Epoxy Patches

Wood and wood products are amongst the most important construction materials. Wood is generally used in frames, buildings, truss roof structures in buildings, bridges, towers, railroad infrastructures, and many more applications. Damage and failure behaviour of wood members in tensile, compressive, or shear loading are extremely important to account for in wooden structures subjected to high working stresses. Wood exhibits its greatest strength in tension in the grain direction. A few applications load a wood member in pure tension, such as trusses in the most varied applications. For a safe design, predictive methods and models for the simulation of the structural behaviour of these elements are required. One of the possible approaches is the finite element method. In this work, the tensile strength of adhesively bonded repairs with carbon-fibre reinforced plastic patches on wood members in pure tension is addressed experimentally and numerically. A parametric analysis was carried out on the overlap length (LO) between the composite reinforcement and the undamaged region of the beam. The numerical analysis used the finite element method and cohesive zone models to simulate damage initiation and propagation in different materials such as the adhesive or wood in different propagation planes. The comparative analysis of the test results and the simulations showed a good correlation between both and provided design principles for these structures. An optimization technique to reduce stress concentrations and eventually increase the repair's strength was also tested numerically, consisting of adhesive filleting at the patch edges. Results showed that this technique can be used to increase the strength of the repairs.

Development of roof trusses with metal plate connectors using domestic plantation timber.

Metal plate connectors (MPCs) were developed and applied to truss assemblies to evaluate the structural performance of Japanese cedar roof trusses in the study. An MPC with a tooth length of 9 mm, a plate thickness of 0.9 mm, and a tooth density of 1 tooth cm^(-2) was designed and produced using SS33 structural steel sheets. The loading capacities of the designed MPC were 216~265 N per tooth, and the derived allowable lateral resistance was 68.3~86.4 N per tooth for Japanese cedar lumber joints in tension. Ultimate bending capacities and stiffness of the 38×140-mm wood roof truss system were 82.6 and 48.9% higher than those of 38×89-mm wood roof truss, respectively. No significant difference was found between Howe and Fink trusses. The critical failures in Japanese cedar roof trusses were located at the heel joint, and these accounted for 75% due to a combination of tooth withdrawal and plate failure in the 38×140-mm truss, and 87.5% due to the tooth withdrawal in the 38×89-mm truss. Flexural deflections of Japanese cedar roof trusses measured at the design load level were within 5.0~20.5% of the design deflection limitation. Furthermore, the designed roof load was only 9.9~18.9% of the ultimate equivalent distributed loads measured at truss rupture, which assures the safety of Japanese cedar roof trusses in service.

Effectiveness of foundation concrete slabs in preventing termite attack on wooden roof trusses

This article examines the effectiveness of foundation concrete slabs in preventing termite attack on wooden roof trusses. Twenty residential bungalow buildings, constructed with hollow sandcrete blocks, were investigated for a period of 5 years. The buildings were grouped into four. The first group belongs to buildings without foundation concrete slabs; the second group is buildings with foundation concrete slab constructed from bush gravel. The third group of buildings has their foundation slabs constructed with crushed granite, manually mixed, while the fourth group belongs to buildings with foundation concrete slab constructed from crushed granite but mechanically mixed. It was discovered that the fourth group of buildings had 100 per cent proof against termite penetration, the third group of buildings had high resistance to termite penetration, but not 100 per cent, while the second group of buildings had limited resistance to termite penetration, and the first group of buildings had no resistance against termite penetration.

The Polonceau Roof and its Analysis

The Polonceau roof truss was one of the most successful roof designs of the nineteenth century. It originated from timber-and-iron construction, but it was quickly adapted to pure iron construction as well. It became very popular for medium to large spans. This paper briefly reports the story of the invention and spread of the Polonceau roof truss. We provide a sketch of the state of technology from which the Polonceau roof truss emerged, and we observe the adaptation of the scheme to pure iron construction. After that, we focus on the various approaches for structural analysis of this kind of roof truss. We identify techniques which were based on the works of Eytelwein and Navier, as well as the more modern truss theory, and we observe the co-existence of both approaches during the nineteenth century. We trace the Polonceau roof truss through the most significant books on structural analysis and analyse how the national traditions in France, England, and Germany influenced the approach towards this type of structure.

Probabilistic Analysis and Optimization of Roof Trusses

The influence of gap between wooden members and displaced nail-plates in roof trusses is investigated by means of probabilistic calculations and structural optimization. The employed mechanical model, using the finite element method, captures the non-linear behaviour of the nail-plate joints. The joint stiffness involves the size and location of the nail-plate, and the presence of contact or gap respectively between the wooden members. The analysis shows that even small initial gaps considerably increase the deflection of a roof truss. Misplaced nail-plates also effect the deflection negatively, but it is also shown that the deflection can be significantly decreased, and the utilization of nail-plates improved, by optimizing the nail-plate positions with respect to critical load cases and requirements.

Restoration of roof truss and the inscription on the construction of the Sheath Hall of Iwaya-kumanoza shrine in Kumamoto prefecture

Restoration of roof truss and the inscription on the construction of the Sheath Hall of Iwaya-kumanoza shrine in Kumamoto prefecture

Strength and behaviour of cold-formed steel offset trusses

Thirteen full-scale truss specimens fabricated with cold-formed steel C-sections were tested to study various practical strengthening techniques in order to achieve a desired behaviour and an increased capacity. Specimens were subjected to concentrated panel point loading simulating the realistic loading condition of a roof truss. Results revealed that local buckling of the top chord (LBTC) adjacent to the heel plate was the predominant failure mechanism. In instances where the heel plate was not adequately stiffened, the distortion or crippling of the plate occurred at failure. For the investigated pitches, an increase in specimen pitch resulted in an increase in the capacity. Strengthening both the top chord adjacent to the heel plate and the heel connection with both a shallow member and a heel plate stiffener resulted in the most significant increase in the capacity compared with the original truss configuration. Beam–column analysis of the top chords in the failure region was performed using both the conventional interaction design equations and the direct strength method as suggested in CSA S136-07.

St Pancras Renaissance hotel, London – a future for the past

This paper looks at the process of appraisal, both in general and in the particular case where it is used to justify a new use for a redundant historic building. The focus of the paper is St Pancras Chambers in London, designed by Sir George Gilbert Scott in the 1860s. Originally one of the great railway hotels, the building was taken into use as offices after the hotel closed in 1935. In the 1980s it was vacated and remained unoccupied for a number of years, with significant deterioration occurring. The building, now grade 1 listed, is undergoing restoration some 140 years after its original design to transform it back to a luxury hotel, the St Pancras Renaissance hotel, with a level of servicing consistent with modern expectations. The work is taking place in close consultation with English Heritage. Intervention has been limited to the extent that this can be sensibly justified, and alterations are generally reversible. The appraisal has focused on the Moreland floors and the condition of the timber roof trusses. The paper sets out the methodology adopted to justify the continuing use of the building in order to give a ‘future for the past’ to this great Victorian building.