The application of steel joists to floor construction can be traced back more than 100 years to the use of a sheet steel joist in the State of New York Bank Building in 1855. Since that time various forms of joists have been developed and exploited. As a result, two general types of joists are now on the market: a) Solid web joists; b) Open web, or truss type, steel joists. In order to determine the strength, stiffness, and behavior of these structural sections under load, representative open web steel joists have been tested at the University of Miami, School of Nursing Building (building about to be demolished). Using two hydraulic jacks to apply the load at eight different locations along the strip, the assessment of the ultimate structural performance of the floor system to positive moments in correspondence of selected strips was possible. After analyzing the data collected from the sensors through the data acquisition system, it was concluded that the results obtained from the Finite Element model were consistent compared to the results obtained from the experimental approach, helping to understand better the behavior of this structural system. A recommendation for further study is enclosed.

This thesis summarizes the results of an experimental investigation involving the testing of push-out specimens with channel shear connectors. The test program involved the testing of 78 push-out specimens and was aimed at the development of new equations for channel shear connectors embedded in solid concrete slabs and slabs with wide ribbed metal deck oriented parallel to the beam. <p>The test specimens were designed to study the effect of a number of parameters on the shear capacity of channel shear connectors. Six series of push-out specimens were tested in two phases. The primary difference between the two phases was the height of the channel connector. Other test parameters included the compressive strength of concrete, the length and the web thickness of the channel. <p>Three different types of failure mechanisms were observed. In specimens with higher strength concrete, failure was caused by the fracture of the channel near the fillet with the channel web acting like a cantilever beam. Crushing-splitting of concrete was the observed mode of failure in specimens with solid slabs when lower strength concrete was used. In most of the specimens with metal deck slabs, a concrete shear plane type of failure was observed. In the specimens involving this type of failure, the channel connector remained intact and the concrete contained within the flute in front of channel web sheared off along the interface. <p>The load carrying capacity of a channel connector increased almost linearly with the increase in channel length. On average, the increase was about 39% when the channel length was increased from 50 mm to 100 mm. There was a further increase of 24% when the channel length was increased from 100 mm to 150 mm. The influence of web thickness of channel connector was significant when the failure occurred due to channel web fracture but was minimal for a concrete crushing-splitting type of failure. <p>The specimens with solid concrete slabs carried higher load compared to those with metal deck slabs. The increase in load capacity was 33% for specimens with 150 mm long channels but only 12% for those with 50 mm long channel connectors. <p>This investigation resulted in the development of a new equation for predicting the shear strength of channel connectors embedded in solid concrete slabs. The proposed equation provides much better correlation to test results than those obtained using the current CSA equation. <p>The results of specimens with metal deck slabs were used to develop a new equation for predicting the shear capacity of channel connectors embedded in slabs with metal deck oriented parallel to the beam. The values predicted by the proposed equation were in good agreement with the observed test values.

This thesis summarizes the results of an experimental investigation involving the testing of push-out specimens with channel shear connectors. The test program involved the testing of 78 push-out specimens and was aimed at the development of new equations for channel shear connectors embedded in solid concrete slabs and slabs with wide ribbed metal deck oriented parallel to the beam. <p>The test specimens were designed to study the effect of a number of parameters on the shear capacity of channel shear connectors. Six series of push-out specimens were tested in two phases. The primary difference between the two phases was the height of the channel connector. Other test parameters included the compressive strength of concrete, the length and the web thickness of the channel. <p>Three different types of failure mechanisms were observed. In specimens with higher strength concrete, failure was caused by the fracture of the channel near the fillet with the channel web acting like a cantilever beam. Crushing-splitting of concrete was the observed mode of failure in specimens with solid slabs when lower strength concrete was used. In most of the specimens with metal deck slabs, a concrete shear plane type of failure was observed. In the specimens involving this type of failure, the channel connector remained intact and the concrete contained within the flute in front of channel web sheared off along the interface. <p>The load carrying capacity of a channel connector increased almost linearly with the increase in channel length. On average, the increase was about 39% when the channel length was increased from 50 mm to 100 mm. There was a further increase of 24% when the channel length was increased from 100 mm to 150 mm. The influence of web thickness of channel connector was significant when the failure occurred due to channel web fracture but was minimal for a concrete crushing-splitting type of failure. <p>The specimens with solid concrete slabs carried higher load compared to those with metal deck slabs. The increase in load capacity was 33% for specimens with 150 mm long channels but only 12% for those with 50 mm long channel connectors. <p>This investigation resulted in the development of a new equation for predicting the shear strength of channel connectors embedded in solid concrete slabs. The proposed equation provides much better correlation to test results than those obtained using the current CSA equation. <p>The results of specimens with metal deck slabs were used to develop a new equation for predicting the shear capacity of channel connectors embedded in slabs with metal deck oriented parallel to the beam. The values predicted by the proposed equation were in good agreement with the observed test values.

The objective of the research reported herein is to present a comprehensive evaluation of all available experimental data from push-out tests utilizing the ELCO Grade 8 standoff screws. The goal is to develop a strength prediction equation and determine reliability parameters compatible with the Load Factor Resistance Design (LRFD) procedure that would allow the use of this shear connector in design of composite floor systems. The study considers results from push-out tests using this type of screw reported by Hankins et al. (1994), Alander et al. (1998), Webler et al. (2000), and Mujagic et al. (2000). Further, this study identifies the limitations in earlier approaches aimed at predicting the strength of standoff screws. An improved strength prediction model is developed that considers all applicable limit states and determines maximum strength of a connector. A reliability study was also conducted to derive strength reduction factors to be used in design. Parameters considered in the model include deck type and geometry, screw height, concrete compressive strength, top chord angle yield strength, and stand-off screw rupture strength. Results from strength prediction model were compared with results from composite joist tests. / Master of Science

Composite construction is widely used worldwide and is undergoing significant technological development. New Zealand is part of this development, with new beam options incorporating multiple unstiffened web openings and new deck profiles supported by extensive testing. However, one area where relatively little research has been undertaken is in the interaction of the composite slab with the seismic resisting system under lateral loading. In order to provide important new information in this area, a series of full scale beam-column-joint-slab subassemblies were tested at the University of Canterbury. Specimens tested had moment end plate connections and different combinations of deck tray direction, and isolation of the slab from the column. An additional test uses a sliding-hinge type connection to assess the effect of the floor slab in this type of low damage connection. In these tests the lateral capacity of the seismic resisting system was increased by up to 25% due to the presence of the slab in contact with the column. The increase in capacity is 10% greater for decking running in longitudinal direction than in the transverse direction as a result of a more substantial full depth slab bearing on the column. The floor slabs of the subassemblies with the slab cast against the column all showed a higher level of damage than for those with the isolated column and the post ultimate strength degradation of the subassemblies without special detailing was significant. The subassembly with a section of full depth slab surrounding the column also exhibited a higher capacity but with an improved post ultimate strength degradation. All moment end plate subassemblies sustained drifts of up to 5% without significant strength loss. The sliding hinge joint showed little signs of damage under testing to 5% drift. Some inelastic deformation of the connection and beams was noted above 5% drift. Results from both testing and numerical modelling have shown that the current methods used to design these systems are conservative but within 15% of the values observed. Further testing and modelling will be necessary before any meaningful changes can be made to the way in which these systems are designed. Recommendations have been made regarding the placements of shear studs in plastic hinge zones and the provision of slab isolation around beam-column connections.

Progressive collapse research aims to characterize and quantify the behavior of different structural systems in events of extreme local damage caused by bombings to improve the performance of targeted structures and to protect occupants. The focus of the research program described herein is the performance of steel gravity frame structures with composite floor systems in column loss scenarios. The goal of the project is to contribute to the development of rational design guidelines for progressive collapse resistance and to assess any potential weaknesses in current design standards. This thesis presents the results of a series of tests performed on a steel frame structure with simple framing connections and a composite floor slab under interior column loss. The specimen was designed and constructed in accordance with typical design practices and was subjected to increasing uniform floor loads after static removal of the central column. No significant structural damage was observed up to a load equivalent to the ultimate gravity design load. Further testing was performed after the deliberate reduction of the capacity of the steel framing connections, ultimately resulting in total collapse of the specimen. / text

Yes / This paper presents an experimental study on an innovative composite floor system that can be demounted and deconstructed. In this system, the composite slab, formed with profiled metal decking, was connected to a steel beam via demountable shear connectors. A full-scale demountable composite floor system specimen was tested to ultimate load bearing capacity and compared with a similar non-demountable composite floor system specimen using conventional welded headed stud connectors. The experimental results and observations showed that the structural behaviour and load bearing capacity of both composite floor systems are very similar. However, the composite floor system with demountable shear connectors could be deconstructed after testing and the composite slab could be easily detached from the steel beam. The comparison and analysis presented in this paper indicated that the simple design methods currently provided in the Eurocode 4 for the welded shear connections could be used to assess the ultimate moment capacity of demountable composite floor systems.

Longitudinal slab splitting in composite hot rolled girders and joist girders was investigated. Two different type of framing configurations were studied with two tests conducted per configuration. The framing configurations were designated as either flush-framed or haunched, which describes the framing of the joists into the joist girders or H-shape. Each floor system consisted of at least one exterior or spandrel joist girder, one interior joist girder, and in three of the four tests, an exterior or spandrel H-shape. The nominal lengths of the girders were 30 ft 4 in. with a centerline spacing of 7 ft for the flush-framed tests and 6 ft 9 in. for the haunch tests. Varying amounts of transverse reinforcement were used in the slab over each girder. Shear connectors were all 0.75 in. diameter headed shear studs of varying lengths. The results of these tests were used to determine the minimum amount of transverse reinforcement required to prevent longitudinal splitting from controlling the strength of the section. A comparative analytical study was performed to generate a design procedure for determining the appropriate amount of transverse reinforcement. This consisted of adapting existing procedures in reinforced concrete for similar shear problems and generating alternative procedures based on existing research for composite construction. Results from these methods were then calibrated against experimental data obtained in this study. / Master of Science

No / Circular economy is an economic system aimed at minimizing wastes and making the most of the current resources. This regenerative approach contrasts with the traditional linear economy, which has been adopted by the construction industry. Developing new construction technologies for sustainable built environment is a top priority for the construction industry throughout the world. Much of the environmental impact from the construction industry is associated with the consumption of resources and generation of waste. The construction industry in Europe consumes over 70,000 million tonnes of materials each year and generates over 250 million tonnes of waste. Composite flooring formed by connecting the concrete slabs to the supporting steel beams has been widely used for many years and is well established as one of the most efficient floor systems in multi storey steel frame building structures. However, shear connectors are welded through the steel decking to the steel beams and cast into the concrete; this made deconstruction and reuse of these components almost impossible. A new composite flooring system which allows for the reuse of the steel beams and composite floor slabs is developed and tested to assess its potential and suitability for reuse. This paper presents the results of a series of full scale beam tests and demonstrates the reusability of this new form of composite flooring systems. Simplified hand calculations are also provided and compared against beam tests / EPSRC, Structural Metal Deck Ltd.

Denna rapport utreder möjligheterna att använda restprodukter som ljudisolering i lägenhetsskiljande mellanbjälklag av trä med spännvidd 6 m. Ett steg mot att uppfylla Sveriges byggindustris nollvision för koldioxidutsläpp är att bygga mer i trä och att återanvända/återvinna restprodukter. Det svenska entreprenadföretaget Skanska har vid sina krossanläggningar ett överskott av material i form av bergkross 0 - 0,2 mm och krossad restbetong. I denna rapport har en prototyp av ett träbjälklag tagits fram med influenser från byggtekniken från sekelskiftet 1800–1900 med avseende på nyttjandet av tung fyllningsmassa som ljudisolering i träbjälklag. Den framtagna bjälklagsprototypen uppfyller de krav som ställts i BBR efter dimensionering enligt Eurokoderna med hänsyn till brand, hållfasthet, svikt och nedböjning. Enligt en simulering i SEAWood, ett verktyg för akustiksimulering som är under utveckling vid RISE Research Institutes of Sweden, uppfylls även kraven på ljudisolering, detta stöds av de analyser som gjorts av mätresultat från liknande bjälklag. Fyllningsmaterialets höga vikt medför att prototypen är ett lågfrekvent bjälklag, detta kombinerat med att simuleringen endast är en indikation på ljudisoleringsegenskaper gör att det kommer krävas praktiska tester för att fastställa prototypens ljudisolerande och dynamiska egenskaper. Den framtagna bjälklagsprototypen är lämplig att prefabricera tack vare en konstruktion med få ingående delar. Att prefabricera bjälklaget har utöver de ekonomiska fördelar det medför stora fördelar ur ett arbetsmiljöperspektiv och är även fördelaktigt ur fuktsynpunkt. För att uppskatta bjälklagets miljöpåverkan gjordes en enklare jämförelse med ett prefabricerat betongbjälklag som visade att utsläppen av koldioxidekvivalenter fram till bruksfasen var mer än dubbelt så stor för betongbjälklaget än för prototypbjälklaget. / This report investigates the possibilities of using residual products as sound insulation in apartment separating timber floors with a span of 6 m. One step towards meeting the Swedish construction industry's zero vision for carbon dioxide emissions is to build more using timber and to reuse/recycle residual products. The Swedish building contractor Skanska has at its quarries a surplus of material in the form of crushed rock of the 0 - 0.2 mm fraction and crushed residual concrete. In this report, a prototype of a timber floor has been produced with influences of construction technology from the turn of the 19 th century regarding the use of heavy filling as sound insulation in timber floors. The developed floor prototype complies with the requirements set in BBR after dimensioning according the Eurocodes regarding fire safety, strength, sagging and deflection. According to a simulation in SEAWood, a tool for acoustic simulation which is under development at RISE Research Institutes of Sweden the requirements for sound insulation are also met, which is supported by analyzes made by comparing with data on similar timber floors. The high mass of the filling material implies that the prototype is a low frequency floor, this in conjunction with the simulation only being an indication of sound insulation properties, it will require practical tests to determine the prototypes sound insulating and dynamic properties. The developed floor prototype is suitable for prefabrication thanks to a design with few components. Prefabrication of the floor has in addition to the economic benefits it brings great benefits from a working environment perspective and is also beneficial from a moisture point of view. To estimate the environmental impact of the timber flooring, a simple comparison was made with a prefabricated concrete floor which showed that carbon dioxide emissions up to the using phase were more than twice that of the concrete floor than for the prototype floor.