Floor Framing Research Articles

Impact Sound Insulation Concept for Lightweight Timber Floor

This paper is the second continuation of lightweight timber frame floor construction investigation with a respect to impact noise isolation. We will log on to previous article which dealt with mockup investigation of new LWTF floor conception. The main objectives of research is to design lightweight floor with good impact sound insulation performance to achieve low cost and reduce thickness of construction. In the following chapters well outline results of new floor model on lightweight timber frame construction implemented in laboratory conditions in Belgian Building Research Institute in Limelette, Belgium.

Dynamic Analyses of Semi-Rigid Connection Low Yield Point Steel Frames

Based on the analysis for 10 series (altogether 50) of finite element analytic models, the time-history analysis is discussed in this paper to investigate the relations between frame parameters of semi-rigid steel frames, these parameters include the frame's floor number, the frame's span number, especially the rotation stiffness of beam-to-column connections. Comparing with the steel frame structure, the ductility of semi-rigid steel frame structure is improved with the reduction in the rotation stiffness of connections. Furthermore, semi-rigid steel frame structure under seismic loads has a good seismic performance.

Dynamic analysis of composite columns in Inelastic state

The main objective of this study is analyzing Seismic behavior of composite columns in frame in inelastic state under dynamic load. Therefore, three type of composite column have been used in this paper. IPB Steel section embedded in concrete (type 1), Concrete-filled thin-walled steel sections (type 2), half concreted IPB sections (type 3) which are designed for 3 and 8 floor frame tenement in plastic way. Three earthquake accelerogram have been used for analyzing model seismic behavior and model analysis has been done in non-linear dynamic analysis with Seismostruct application. The results demonstrated that frame designed by composite columns type 1 and 3 in the flexural behavior, have similar construction behavior in the way that plasticity, softness and good function to dispose lateral forces are the same. Although Type 2 composite model have large sections, have poor performance in tolerating flexural moment. This event refers to poor role of concrete in tension. On the other hand, the amount of concrete is important in Withstand compressive forces and in constructions with high compressive forces, type 1 and 2 have better performance.

Fire Resistance of Wood Truss Floor Assemblies

This paper discusses the factors that affect the fire resistance performance of lightweight wood frame unrestrained floor assemblies protected with Type X gypsum board ceiling finishes. Twenty-two fire resistance experiments were conducted on full-scale load-bearing wood joist floor assemblies using the ULC standard fire exposure time–temperature curve that is similar to ASTM E119 standard. Parameters investigated in this study include the effects of gypsum board screws spacing from board edges, insulation installation, insulation type, joist spacing for assemblies with gypsum board attached to resilient channels, joist depth, resilient channel installation, resilient channel spacing, sub-floor topping, number of sub-floor layers, and load magnitude. The impact of these parameters on the fire resistance of wood joist frame floor assemblies is discussed. The fire resistance of wood frame floors appears essentially to be governed by the gypsum board screw spacing from the board edges and the type of insulation in assemblies with one layer of gypsum board and by the resilient channel spacing and the gypsum board screw spacing from the board edges in assemblies with two layers of gypsum board. The effects of other parameters in assemblies with two layers of gypsum board such as the joist spacing where the gypsum boards are attached to resilient channels, installation of resilient channels, insulation installation, insulation type, adding gyp-crete topping above the sub-floor and number of sub-floor layers on fire resistance are relatively insignificant.

Solid Science

At Pennsylvania State University’s new Millennium Science Complex, the exacting requirements of modern research laboratories and the advanced scientific instruments used therein led to a design that features floor framing heavier than usual and extremely rigorous vibration control measures. To make the project even more challenging, the design called for dramatic cantilevers and the presence of an open garden space located directly above the most critical laboratories.

Structural Response of World Trade Center Buildings 1, 2 and 7 to Impact and Fire Damage

The National Institute of Standards and Technology (NIST) conducted an extensive investigation of the collapse of World Trade Center towers (WTC 1 and WTC 2) and the WTC 7 building. This paper describes the component, subsystem, and global analyses performed for the reconstruction of the structural response of WTC buildings 1, 2, and 7 to impact and fire damage. To illustrate the component and subsystem analyses, the approach taken for simulating the performance of concrete slabs and shear stud connectors in composite floors subject to fire conditions are presented, as well as steel floor framing connections for beams and girders. The development of the global models from the component and subsystem analyses is briefly described, including the sets of input data used to bound the probable conditions of impact and fire damage. The final analysis results that were used to develop the probable collapse hypotheses, and a comparison of the results against observed events, are presented for each building. A review of research activities focused on improving understanding of structural system response to multi-floor fires following the WTC disaster is also provided.

Optimization method for building envelope design to minimize carbon emissions of building operational energy consumption using orthogonal experimental design (OED)

Climate change has drawn the attention of many researchers and practitioners to focus on the methods to address the challenges in achieving low-carbon buildings and cities and in future developments. Nevertheless, few studies have explored the application of orthogonal experimental design (OED) method to optimize building design for the lowest carbon emissions of building operational energy consumption. This paper aims at developing a new optimization method to building envelope design for the lowest carbon emissions of building operational energy consumption using OED. Firstly, according to the basic principles of the building heat transfer, the method of building’s energy consumption calculation is analyzed, which includes the simplified algorithm based on steady-state heat transfer theory and the dynamic simulation based on the unsteady heat transfer theory. The classification of the building energy consumption influencing factors are then investigated and discussed. Furthermore, based on the basic concept and principle of OED, a case study from the perspective of OED has been conducted, which involves a public building in Nantong, Jiangsu province. Six influence factors of building envelope to building operational energy consumption are selected as follows: exterior wall type, window frame type, glass type, roof type, floor type, and shading type. Selection of optimal case is then determined by the index that is based on the year-round accumulative total load. In the end, Tianzheng Building Energy Consumption Software is used to calculate the optimal case operational energy consumption. The research would provide a new optimization method for building envelope design to the lowest carbon emissions of building operational energy consumption.

EXPERIMENTAL STUDY ON SHEAR BEHAVIOR OF THICK STRUCTURAL PLYWOOD SHEETED FLOOR FRAMING WITH OPENING

EXPERIMENTAL STUDY ON SHEAR BEHAVIOR OF THICK STRUCTURAL PLYWOOD SHEETED FLOOR FRAMING WITH OPENING

Treatment of Brick Wall Systems in Early 20th Century Korea

This paper, which aims to identify the structure and fabric of buildings using the brick structure during modern times in Korea, focuses on connection details at foundation, each floor and roof as the most important structure components in the exterior wall through 21 architectural technical books and investigating 44 existing brick structures in the early 20th century. As a result of findings the following details could be identified. The most important concerns in the exterior wall at ground level include the formation of the foundation and bearing wall to resist lateral earth pressure in case of basements, and the installation of damp-proof courses to block damp from the ground. Other than floor frames with traditional wood girders in the exterior walls adjacent to the floor, concrete slabs with steel girders and reinforced concrete slabs have been introduced. Roof sections interlocking with exterior walls can be divided into three types, those with projecting eaves, those interlocking with the exterior wall, and those hidden behind the parapet. Unlike the eaves in traditional wood structures, the types of roof interlocking with the exterior wall for brick structures have appeared most in religious buildings. Other than these buildings, the advent of parapets to completely hide the eave line foresaw new types of buildings.

Design and Model Analysis of City Bus Body Frame Based on ANSYS

Applying the 3D design and finite element technology to the design of city bus body, the model analysis of bus body frame was carried out. On the basis of general modeling of bus body, the locus of bus body frame was constructed in light of the inner surface profile of body cover panel. The 3D models of both bus body frame and floor frame were constructed under Pro/E, and the virtual assembly of them was completed. By leading the wire frame model of bus body frame in ANSYS software, its FEA wire frame model was obtained. The natural frequency and vibration mode of bus body frame can be known by means of model analysis. It lays the foundation for the FEA of whole bus body frame.

A New Fire Resistant Light Mineral Wool

A comprehensive research project on the fire performance of a new light mineral wool has been carried out at ETH Zurich in collaboration with the Swiss Federal Laboratories for Materials Science and Technology (EMPA). A large number of small-scale fire tests permitted the analysis of different parameters on the fire performance of the new mineral wool. The results of the fire tests allowed the verification and calibration of thermal properties used for thermal finite element (FE) analysis. Based on an extensive FE parametric study, the coefficients for the new mineral wool to be used in the design model for the verification of the separating function of light timber frame wall and floor assemblies were calculated. The paper first describes the main results of the experimental and numerical analyses. Then, the calculation of the coefficients for the new mineral wool to be used in the design model are presented.

Seismic-Resistant Investigation of Multi-Storey Building by Response Spectrum Method

The present article attempts to evaluate the earthquake resistance of a four-storey building frame. It also compares the performance of buildings with soft ground floors and different infill parameters, such as brick wall and shear wall. The Indian standard code (IS-code) of practice (IS: 1893, Part-1:2002) guidelines and methodology are used to analyze the problem. Response spectrum method, involving various modal participations, is employed to evaluate the nodal forces in the typical beam-column junctions. The frame members, infill walls and floors are tackled as rigid end joints, panel element, and diaphragms rigid in-plane, respectively. Linear elastic analysis is performed with individual floor mass and stiffness, taking into account the building as a multiple degrees of freedom system. The effect of damping and the soil criteria are also studied as per the provision of IS-code. The investigation concludes that the proper mass and stiffness distribution in multi-storied buildings will minimize the hazardous effects of seismic excitation. The mathematical model of the building finally recognized the hazardous features of Indian reinforced concrete buildings and recommends some measures to improve the seismic performance.

Topology Synthesis of Multicomponent Structural Assemblies in Continuum Domains

This paper presents a new method for synthesizing structural assemblies directly from the design specifications, without going through the two-step process. Given an extended design domain with boundary and loading conditions, the method simultaneously optimizes the topology and geometry of an entire structure and the location and configuration of joints, considering structural performance, manufacturability, and assembleability. As a relaxation of our previous work utilizing a beam-based ground structure, this paper presents a new formulation in a continuum design domain, which enhances the ability to represent complex structural geometry observed in real-world products. A multiobjective genetic algorithm is used to obtain Pareto optimal solutions that exhibit trade-offs among stiffness, weight, manufacturability, and assembleability. Case studies with a cantilever and a simplified automotive floor frame under multiple loadings are examined to show the effectiveness of the proposed method. Representative designs are selected from the Pareto front and trade-offs among the multiple criteria are discussed.

Using Sea Turtle Carcasses to Assess the Conservation Potential of a Turtle Excluder Dredge

AbstractFisheries observers have documented interactions between sea turtles in the family Cheloniidae and the Atlantic sea scallop Placopecten magellanicus fishery. Sea turtle injuries resulting from interactions with scallop dredges are being mitigated through shifts in fishing effort and modifications to fishing gear. The standard New Bedford dredge can trap objects and crush them as they pass between the dredge frame and sea floor, so a modified turtle excluder dredge has been designed to reduce the likelihood of a turtle's passing under the frame when the dredge fishes on the seafloor. The key elements of the modified design are a forward cutting bar (which results in a sloping rather than a vertical face), a reduced number of bale support bars (just the center and outer bales), extension of the outer bale bars before tapering to the gooseneck (hauling point), and a reduction in the sources of entrapment between the depressor plate and the cutting bar via reduced spacing of struts. We evaluated the ability of the modified dredge to cause live sea turtles to pass over it by using loggerhead sea turtle Caretta caretta carcasses as a proxy. The carcasses were placed on the seafloor in the path of a towed dredge equipped with video cameras. Nine interactions between carcasses and the modified dredge were documented on video recordings. In each of the interactions, the carcass hit the dredge and passed over the dredge frame with little or no physical damage to the recovered carcasses. These carcass studies suggest that the turtle excluder dredge reduces sea turtle injuries associated with interactions between sea turtles and scallop dredges fishing on the seafloor.

Design model for the verification of the separating function of light timber frame assemblies

In order to limit fire spread by providing adequate fire compartmentation, elements forming the boundaries of fire compartments are designed and constructed in such a way that they maintain their separating function during the required fire exposure (insulation and integrity criteria). While fire tests are still widely used for the verification of the separating function of light timber frame assemblies, design models are becoming increasingly common. A comprehensive research project on the separating function of light timber frame wall and floor assemblies with cladding made of gypsum plasterboards and wood-based panels was carried out at ETH Zurich in collaboration with the Swiss Laboratories for Materials Testing and Research (Empa). The objective of the research project was the development of an improved design model for the verification of the separating function of light timber frame wall and floor assemblies. A large number of small-scale fire tests permitted the analysis of different parameters on the thermal behaviour of protective cladding made of gypsum plasterboards and wood-based panels. The results of the fire tests allowed the verification and calibration of thermal properties used for thermal finite element (FE) analysis. Based on an extensive FE parametric study, the coefficients of the design model for the verification of the separating function of light timber frame wall and floor assemblies were calculated. The design model was verified by means of full-scale fire tests. The paper first describes the basic structure of the design model for the verification of the separating function of light timber frame wall and floor assemblies. Then, the main results of experimental and numerical analyses are presented. The results permitted the calculation of the coefficients of the design model for the verification of the separating function of light timber frame wall and floor assemblies.

Fire Resistance of Steel C-Joist Floor Assemblies

This paper discusses the factors that affect the fire resistance performance of lightweight steel-framed (LSF) unrestrained floor assemblies protected with Type X gypsum board ceiling finishes. Sixteen fire resistance experiments were conducted on full-scale load-bearing steel C-joist floor assemblies using the ULC standard fire exposure time–temperature curve that is similar to ASTM E119 standard. Parameters investigated in this study include the effects of insulation installation, insulation type, joist spacing, resilient channel installation, resilient channel spacing, type of sub-floor layer and number of sub-floor layers versus number of gypsum board layers. The impact of these parameters on the fire resistance of steel C-joist frame floor assemblies is discussed. The fire resistance of LSF floors appears to be essentially governed by the number of gypsum board layers, spacing of the joists or resilient channels where the gypsum boards are attached, sub-floor type and insulation type. Other parameters are of secondary importance.

Quantifying and Enhancing Robustness in Steel Structures: Part 2--Floor Framing Systems

The objective of this two-part manuscript is to provide information that can lead to: (a) better understanding of disproportionate collapse in structural steel framing systems; (b) improved understanding of secondary load paths that form within structural steel framing systems in the event of a localized failure; (c) development of minimum general structural integrity provisions for structural steel framing systems analogous to those present in ACI 318; (d) recommendations for minimum tie forces that can be used as the basis of indirect design methodologies for structural steel framing systems; (e) an understanding of the distribution of tensile forces within typical steel floor framing systems to facilitate compartmentalization damage or collapse; and (f) identification of simple and economical means with which to enhance the robustness in the typical structural steel framing system.

Charring model for timber frame floor assemblies with void cavities

Design models of timber structures in fire usually take into account the loss in cross section due to charring of wood and the temperature-dependent reduction of strength and stiffness of the uncharred residual cross section. For timber frame wall and floor assemblies with void cavities, only a little information is available. In the first part of the paper, the results of an extensive FE-thermal analysis on initially protected timber beams exposed to fire on three sides, after the fire protection has fallen off (post-protection phase), are presented. The FE-thermal analysis verified by fire tests on protected timber specimens exposed to one-dimensional charring permitted the analysis of the main parameters, which influence charring during the post-protection phase. Based on the FE-results, a charring model for timber frame floor assemblies with void cavities has been developed and is presented in the second part of the paper. The charring model takes into account the influence of high temperature during the post-protection phase as well as the heat flux superposition on the charring rate of the timber beams exposed to fire on three sides.

Fire Resistance of Wood Joist Floor Assemblies

This paper discusses the factors that affect the fire resistance performance of lightweight wood frame unrestrained floor assemblies protected with Type X gypsum board ceiling finishes. Twenty-two fire resistance experiments were conducted on full-scale load-bearing wood joist floor assemblies using the ULC standard fire exposure time–temperature curve that is similar to ASTM E119 standard. Parameters investigated in this study include the effects of gypsum board screws spacing from board edges, insulation installation, insulation type, joist spacing for assemblies with gypsum board attached to resilient channels, joist depth, resilient channel installation, resilient channel spacing, sub-floor topping, number of sub-floor layers, and load magnitude. The impact of these parameters on the fire resistance of wood joist frame floor assemblies is discussed. The fire resistance of wood frame floors appears essentially to be governed by the gypsum board screw spacing from the board edges and the type of insulation in assemblies with one layer of gypsum board and by the resilient channel spacing and the gypsum board screw spacing from the board edges in assemblies with two layers of gypsum board. The effects of other parameters in assemblies with two layers of gypsum board such as the joist spacing where the gypsum boards are attached to resilient channels, installation of resilient channels, insulation installation, insulation type, adding gyp-crete topping above the sub-floor and number of sub-floor layers on fire resistance are relatively insignificant.

Examination of North American softwood lumber species substitution using discrete choice preferences and disaggregated end-use markets

Over the past 20 years, four significant and contentious softwood lumber trade disputes have taken place between the United States and Canada. The US International Trade Commission (USITC), relying on aggregate market assessments using elasticity of demand estimation and cointegration methods, has ruled that all North American softwood lumber species are perfectly fungible. The objective of this study is to disaggregate the US softwood lumber market by estimating cross-price elasticity of demand for North American softwood lumber species and species groups in three major end-use markets (floor framing, roof framing, and wall framing products) using a discrete choice preference model. Specifically, this study utilizes a choice-based conjoint model to estimate species and species group preferences, market shares, and price-demand relationships for North American softwood lumber. Research results are compared with published aggregate market cross-price elasticity of demand estimates, such as those relied upon by USITC, to determine whether North American softwood lumber species and species groups are perfectly fungible in the three largest softwood lumber end-use markets. Results demonstrate that distinct differences exist in the substitutability between North American species and species groups of softwood lumber. The results provide notable implications in future USITC trade analyses of the US–Canadian softwood lumber trade issue.