The following project work studies trusses and roof structures and their performance during a fire in terms of rules and requirements that needs to be considered. Determination of how resistant truss or roof construction is still heavily dependent on the subjective experience and assessment of professional. It means that nowadays stages of this defining of fire resistance of roof/truss are still in need of clarification. The load combination for accidental load is compared to the ultimate limit state during the fire and it was showed that the loads were lower. The strength of timber during the fire was calculated by the two methods. Calculations by both methods revealed that timber used in construction can withstand fire by 0 minutes. However, fire resistance of the wooden materials can be improved by different techniques that were described in this study. The biggest improvement of fire resistance can be achieved with the help of covering - gypsum boards and rockwool, or even with wooden covering if lower protection is needed. As well, many fire-retardant treatments were developed that can improve wood performance during fire by slowing down the spread of fire, by limiting the building up of smoke and other volatiles. Instead of fire-retardant treatment fire retardant paints can be used too. This study showed stages of establishing fire requirements of wooden roof structures by two examples. In this study, two calculations were performed for two different house types, a family house, and an apartment building, to compare the difference between normal load dimensioning and fire load dimensioning. In the fire load dimensioning method, two different times were considered - R30 and R60 load capacity. When calculating the normal load dimensioning, it has been shown that an unprotected truss has no fire resistance, and that the truss has a fire resistance, with respect to bearing capacity, which corresponds to R0, which means that it must be protected for the required time. / Samhällsbyggnad / Husbyggnad / Konstruktion

Falls continue to be a major problem in the residential construction industry and account for a large number of injuries and fatalities each year (US Department of Labor, 2012).  The effects of a fall are catastrophic to the workers and their families as well as the construction company and surrounding community.  Prevention of these incidents has been the primary focus of organizations such as the Occupational Safety and Health Administration (OSHA).  To reduce the number of falls on residential construction sites, OSHA has put forth several standards that require the use of fall protection.  Although guidelines have been provided, there have been concerns and complaints regarding the standards as well as methods and materials that should be used. The goal of this research was to measure the behavior of a five truss roof system with various anchor points and bracing configurations loaded by a horizontal force.  A lab built roof system was used to test three different anchor types with three forms of temporary bracing.  The materials and methodology used in this testing were based on common materials and practices currently used in the residential construction industry. The results of this research show that anchors must engage multiple trusses to spread the applied load throughout the roof system.  Several forms of temporary bracing such as lateral, diagonal, and sway bracing, are also required to strengthen the roof system allowing it to withstand an applied load. / Master of Science

Under the direction of the Federal Highway Administration the Long Term Bridge Performance Program (LTBP) selected Minnesota Bridge number 5718 as a pilot bridge for evaluation. This program focuses on the monitoring of bridges for a 20-year period to understand the structural behavior over time due to the various loads and weathering. In monitoring this bridge a better understanding can be acquired for the maintenance issues related to the nation's deteriorating bridge infrastructure. Bridge Number 5718, which is located just outside of Sandstone Minnesota, is a steel truss bridge that spans the Kettle River. Constant monitoring of the bridge along with periodic testing of the bridge will allow for the collection of data over a 20-year period. The focus of this work is to establish a baseline for the bridges characteristics through nondestructive dynamic testing. Later tests will be compared to these results and changes can then be tracked. In order to perform the required testing, two electromagnetic shakers were used to produce the excitation. The bridge was also outfitted with an array of velocity transducers to allow for the response to be recorded. The data was then used to extract the resonant frequencies, mode shapes, and damping ratios. A modal assurance criterion was also performed to solidify the findings. These parameters define the structural identity of the bridge. Through performing these tests the database that is being collected under the Long Term Bridge Performance Program will be used to better the overall health and safety of the nation's bridges.

The aim of the diploma thesis is a design and an assessment of steel structure of Sports hall. The load-bearing structure consists of arched truss girders. Model dimensions are 55 x 45 m. The arched girders are simply supported to the foundation. The girders are connected with the purlins and the girts. The stability of the structure is provided by lateral and longitudinal bracings.

This thesis deals with design and static assessment of steel structures buildings for storage purposes. The work contains a static calculation performed by software Scia Engineer, manual examination of selected bars and drawings proposed design solution.

Diploma thesis describes the design of roofing for the monastery Rosa Coeli. The initial thought to perform the revitalization of this complex via this way was formed after an exhausting research. At its current state, the Rosa Coeli is sought after and is very popular among tourists; however, as an object, it has a fairly limited impact to everyday life of residents of the city Dolní Kounice. The roofing will, understandably, change the character of the building. As such, it will be usable during the entire course of the year – not only for one-off events. The construction of the timber roof truss consists from solid features, where the chief endeavor was to preserve the unique genius loci.

No description available.

In single storey industrial buildings, the most common material used for the load-bearingsystem is steel. The load bearing system can be designed in different ways. The two mostcommon load-bearing systems of steel industrial buildings are portal frame and thetruss/pillar-system. The benefit of using these systems is the possibility of having largespan structures. These systems have also a high load capacity in function of its weight.Geometrical parameters like width, height, length, and roof slope of the building effectsthe design and the selection of which load-bearing system will be more suitable.The purpose of this thesis is to compare the two systems in terms of weight of steel, priceand global warming potential (GWP) and to see how the load-bearing systems differ. Tofulfil the purpose, it is necessary to find the geometrical parameters to design an optimalportal frame system and use the same parameters in order to design the truss/pillarsystem. By using the same geometrical parameters, the two systems can be comparable.The results of this thesis show that the truss/pillar system has less weight, lower price andlower global warming potential than the portal frame.As conclusions of this parametrical study, it was seen that the truss/pillar system isperforming better than the portal frame system. In general, it is not possible to say that thetruss/pillar-system is better. This is because this thesis work did not consider amongstithers the bracing system, foundation, connections, mounting or fabrication. But it ispossible to say that the differences between the two systems are not major.

This document will outline the findings of three separate and independent studies: Study 1: In or around 1972, an experimental building was constructed. One of the intents of the construction project was to demonstrate advancements in wood building construction design. It was value-engineered throughout. That is, its materials and systems were intended to function at or near design capacity. In 2019, part of the roof of the structure collapsed. This case study investigates two potential factors that led to the failure: stress concentration in excess of the 12 allowable stress for 2 × 4 web members and insufficient plywood sheathing to support live loads 13 caused by large rain events. Study 2: As a building material, cross laminated timber (CLT) has exponentially grown in popularity recently. Although performing superior to numerous other popular building materials, a consistent issue presented in wood construction is the effect of moisture on performance. This study looks to investigate the effect of moisture content on the performance of a 2-way dowel type fastener system loaded in shear perpendicular to the major strength axis. It was found that the peak load capacity of the specimens was not affected by the moisture content of the CLT. However, yield strength increased as the moisture content decreased. Lastly it was found that the failure mode changed from ductile to brittle as specimens became drier than 12% moisture content by mass. Study 3: Inherently, the weak point of any structure is the connection system. This phenomenon is particularly apparent in wooden structures as dowel type fasteners place tremendous amounts of stress perpendicular to the grain of the wood, as well as shear stress under the bolt. In hopes of mitigating this behavior, fiberglass reinforcement of these samples is examined to see if both failure mode as well as overall performance of these fasteners could be improved with reinforcement. It was found that fiberglass significantly reduced the standard deviation of failure strength of fasteners, significantly increased the overall strength of the fasteners, increased the efficiency of the fasteners, and finally increased the probability of bearing failure opposed to block shear failure.

The alternative seismic design provisions for diaphragms provided in ASCE 7-22 Minimum design loads and associated criteria for buildings and other structures Section 12.10.3 account for both diaphragm ductility and displacement capacity, producing more accurate design forces and decreased detailing when compared to conventional seismic design methods. However, the diaphragm design force reduction factor has not yet been determined for tension-only roof truss diaphragms, a common system used in metal buildings. In this study, experimental tests of two cantilevered diaphragm subassembly specimens with tension-only rod bracing were conducted to determine the load-deformation behavior of the system. The first specimen used 7/8-in. rods, two types of hillside washers, two types of compression members, and two configurations of lateral bracing. The second specimen used 3/4-in. rods, one type of hillside washer, one type of compression member, and one configuration of lateral bracing. Four tests were conducted. One additional test was conducted on each specimen to determine the friction in the test setup. The system developed significant ductility during testing and the yield mechanism was primarily tensile yielding of the rods. The results indicate that a diaphragm design force reduction factor of 2.0 for structures with periods greater than 1.0 second and 1.7 for structures with periods between 0.12 and 0.5 seconds may be appropriate for metal building systems if the lateral bracing of the compression member is prevented from buckling.