Tension and Compression force deformation data from laboratory tests of angle segments are used to generate moment rotation curves for the following bolted partially restrained connections: (1) top and seat angle, (2) double web angle, and (3) top and seat angle with double web angles. The force deformation and moment rotation curves are analytically described by a four parameter formula which provides the basis for the analytical connection model. These connection models consist of rigid bars and nonlinear springs representing the angle segments in either tension or compression. Design curves giving the four parameters of the moment rotation curves are generated for the double web angle connection. These parameters are primarily a function of the angle thickness, gage length of the angle legs in flexture, and the number of bolts in the connection. Comparisons of derived moment rotation curves are made with published results of full scale tests.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1989. / Vita. Abstract. Includes bibliographical references (leaves 76-77). Also available via the Internet.

In Limit States Design for steel structures, single plate connections are designed to transfer beam shear to supporting member. These connections, with the connection plate shop-welded to the supporting member and field-bolted to the supported beam are becoming increasingly popular due to their economy and ease of fabrication. Single plate connections are very suitable for cases where speed of erection is a primary consideration. They are particularly superior for skewed connections. Traditional design methods which deal with connection problems generally give over-conservative solutions to this complex problem. Two series of experimental investigations of single plate connections for beam-to-girder webs were conducted. A variety of connections were tested to demonstrate their feasibility and to collect data for analytical correlation studies. The ultimate goal of these tests and studies is to devise a rational basis for the design of these connections. This work is part of a comprehensive research project and the reader is referred to other papers (References 1 and 2) for completeness. Based on experimental results and theoretical correlation studies, a modified design formula is proposed in order to predict the ultimate capacity of single plate connections. The formula tries to incorporate the influences of applied loads (shear force, torsional moment, and bending moment), resistance of the single plate connection, skew angle of the connection plate and type of holes (slotted and standard) used in the connection. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

A practical method of incorporating realistic flexible connections including the effect of connection sizes and shear deflection in plane frame analysis is presented. The general algorithm can be easily implemented in a standard plane frame analysis program and once implemented it can be an ideal tool for production work in the steel industry. In this approach connection stiffness is programmed directly into the analysis by utilizing the connection moment-rotation equations developed by Frye and Morris but it may also be entered separately as data. Nonlinear connection analysis is carried out by the procedure outlined by Frye and Morris. Practical application of this method of analysis is demonstrated by modifying a standard plane frame analysis program to include the effect of flexible connections. The validity of the modified program, CPlane, was verified against the findings of Moncarz and Gerstle. Using CPlane, a simple plane frame structure was analyzed under various lateral load intensities for different connection assumptions. It was found that the inclusion of connection behavior significantly altered the internal force distribution and design of the structure. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

During propped construction the steel-concrete composite action resists dead as well as imposed loads. Conversely, the steel section alone resists the floor self-weight in unpropped beams. The major difference between propped and unpropped composite beams lies in the ductility requirements rather than in the strength requirements. Relatively few studies have been carried out to assess the rotation requirements for unpropped semi-continuous composite beams. The outstanding critical factor in the case of unpropped construction is the dead load stress that must be carried by the steel beam alone prior to hardening of the concrete. This research overcomes the difficulties involved in modelling the composite and noncomposite stages by using a numerical integration technique developed from the basic principles of structural mechanics. The method incorporates the fully non-linear material properties and requires very little assumption. The technique was initially validated using the experimental results from plain steel beam bending tests. The subsequent comparison between the model predictions and the results from the large-scale frame test carried out for this research purpose, showed that the method is capable of predicting non-elastic load vs. end rotation behaviour within a high degree of accuracy. Thus the model can be used with confidence in order to predict the connection rotation requirements for a wider range of loading configurations than is practically possible from experimental testing alone. A parametric study is carried out using the numerical integration technique developed for the semi-continuous composite beam on a total of 2160 different beam configurations, utilising different steel grades and loading conditions. In this study the influence of dead load stress on the connection rotation requirement has been thoroughly evaluated along with several other factors including span to depth ratio, location within the building frame, ratio between the support (connection) moment capacity and span (beam) moment capacity, loading type, steel grade and percentage of the beam strength utilised during design. The connection rotation capacity requirements resulting from this study are assessed to establish the scope for extending the use of composite connections to unpropped beams. The large-scale experiment that has been carried out provided an opportunity to investigate the behaviour of a modified form of composite connection detail for use at perimeter columns (single-sided composite connections) with improved rebar anchorage. Additionally, another extensive parametric study is carried out using the numerical integration technique developed for the steel beam to establish the influence of strainhardening on elastic-plastic frame instability design.

No / This paper describes the experimental results of ten fire tests on medium-scale restrained steel sub-frames to investigate the relative behaviour and robustness of different types of steel joint in steel framed structures in fire. The ten fire tests were designed to investigate the effects of two column sizes (simulating two different levels of axial restraint to the connected beam) and five different types of joint, including fin plate, web cleat, flush endplate, flexible endplate and extended endplate connections. Each test frame, in the form of “rugby goalpost” consisting of one beam and two columns, was connected through two identical beam to column joints. All the steelwork was unprotected except for the top flange of the beam which was protected to simulate the effect of a concrete slab in reducing the beam top flange temperature. The column ends were restrained to examine the effects of axial restraint on the beam and the joints. This paper presents the observations of structural fire behaviour, including joint failure modes and beam limiting temperatures, the development of deflections at beam middle span and axial forces in the joints at elevated temperatures. The main conclusions are: (1) failure (fracture) was observed only in joints when the beam was in catenary action and a variety of joint failure modes were observed which provides valuable data in understanding joint behaviour; (2) the medium-scale steel beams were able to undergo very large deflections View the MathML source without failure; (3) the specimens with stronger connections such as extended endplate reached higher than their limiting temperatures, defined as the beam bottom flange temperature at middle span at which the axial load in the beam returned to zero. But the difference in beam limiting temperatures using different types of joint is small, less than 50 °C; also the column size had little effect (less than 30 °C) on the beam limiting temperature; (4) the beams connected to the larger column experienced less deflections, but higher axial force due to the higher axial restraint to the beam, which led to fracture of the joint components in these tests; in contrast, the lighter columns visibly deformed and formed plastic hinges at the joints, but there was little evidence of connection fracture in the test frames using the light columns; (5) the web cleat connection appears to have the best performance.

With the development of lightweight steel beam and steel joist-concrete slab floor systems, floor vibration problems are becoming more and more prevalent. This paper presents the experimental and analytical study of the vibration characteristics of steel joist and joist-girder members. Three aspects were studied to prevent and correct vibration problems. Long span-joists and joists-girders, with a span greater than forty feet, have not been considered for Murray's criterion and the Modified Reiher-Meister scale. This study shows that these two methods can be used to predict the acceptability of a long span floor system to the occupants. Modifying existing floors so that they will be considered acceptable to the occupants is a concern for existing vibrations problems. This study has shown that by adding additional steel to the bottom chord of the joists and/or joist-girders the floor system frequency can be modified so that the floor will be considered acceptable to the occupants. Predicting the effective moment of inertia of joists and joist-girders is essential to accurately predict the frequency and displacement of a floor system due to human occupancy. This paper presents two new equations that can be use to predict the effective moment of inertia of round web joist and angle web joist and joist-girders based on their span-to depth ratio. / Master of Science

Thesis (Ph. D.)--Lehigh University, 2003. / In three parts. Includes vita. Includes bibliographical references (leaves 770-775).

No description available.

No / Based on temperatures measured in steel joints with different extents of fire protection, this paper proposes a simple method to calculate temperatures in steel joints with partial intumescent coating fire protection. The method combines the simple temperature calculation methods in EN 1993-1-2 (Committee of European Normalisation CEN, Eurocode 3: design of steel structures—part 1-2: general rules—structural fire design, 2005) for unprotected and protected steel structures through the introduction of an exposure factor, which is the ratio of the unprotected surface area of the joint region to the total surface area of the joint area. Using the measured temperatures for fully protected steel joints, this paper first extracts the effective thermal conductivity of the intumescent coating used in the fire tests. Afterwards, this paper presents validation results based on fire test results on joints with partial fire protection. Finally, this paper presents methods to calculate the exposure factor for different types of partially fire protected steel joints.