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The use of glued in rods as a method for connecting timber has received much attention over the past decade with an increasing number of examples of their use in industry. The objective of this study is to understand the failure mechanism of a moment resisting portal frame connection in timber using glued in steel rods. A series of pull out tests are used to determine axial strength of glued in rods with varying anchorage length and bond line thickness. The results are compared with the current design equations and the discrepancies are highlighted. Further pull out tests using rods glued in at angles are used to assess the influence of lateral loading on the axial pull out strength. Small amounts of lateral loading combined with axial loading are seen to significantly reduce the pull out strength of glued in rods and splitting failures are seen at relatively low levels of load. The findings from the pull out tests are used to design a portal frame connection and the moment capacity is estimated using linear elastic analysis. Results from the destructive testing of the portal frame connection are presented and parallels are drawn between the observed behaviour in the angled pull out tests. The linear elastic analysis is found to accurately predict the failure load of the tested connection. The moment rotation (M - ϕ) relationship of the portal frame connection is extracted from the measured test data.

This article presents an efficient method for inelastic analysis of semirigid planar steel frameworks. A compound element comprised of a plastic-hinge element and a semirigid connection element is located at member ends that may potentially undergo inelastic deformation. Nonlinear inelastic flexural behaviour is modeled by an empirical relation between moment and rotation for which the parameters are available from experimental results. A four-parameter model is employed to simulate the nonlinear moment-rotation behaviour of semirigid connections. The member stiffness matrix involving the compound element is expressed explicitly in terms of stiffness degradation factors that vary depending on the loading level. This permits direct account for the combined influence of inelastic and nonlinear connection behaviour on structure stiffness. A semirigid steel portal frame is analyzed to illustrate the proposed analysis method, and the results are compared with those obtained from experiments involving the same frame.

Traditionally, the steel portal frame design assumes that beam-to-column joints are rigid or pinned. Rigid joints, where no relative rotations occur between the connected members, transfer not only substantial bending moments, but also shear and axial forces. Alternatively, pinned joints are characterised by an almost free rotation movement between the connected elements preventing the bending moment transmission. Despite these facts, it is largely recognised that the great majority of joints does not exhibit such idealised behaviour. These joints, called semi-rigid, should be designed according to their actual structural behaviour. Considering all these facts one of the main objectives of this investigation is to propose a modelling strategy to represent the dynamical behaviour of semirigid joints under dynamic actions. The developed finite element model included geometric nonlinearities and considered the influence of non-linear and hysteretic joint stiffness. The updated Lagrangean formulation is used to model the geometric non-linearity. The mathematical model calibration was made based on comparisons to semi-rigid tests and other numerical models [1],[2] and proving to be in accordance to them. However, it must be emphasized that cautions should be taken on the direct use of the results in structural design. The main reasons for this affirmative are related to the occurrence of very important distortions due to the consideration of the semi-rigid joints geometric non-linearity effects on the steel portal frames dynamical response.

Much progress has been made in recent years towards analytical modeling of the limit states behavior of structural steel frame members, connections and systems. Analysis methods that accurately represent the behavioral effects associated with both system and primary member design limit states have been suggested and referred to by many as “advanced analysis” approaches. By use of advanced analysis, the checking of certain limit-states equations in design standards is superceded. Specifically, in an advanced analysis, the checking of member and system stability is directly included within the analysis. If the global stiffness of the structural model is positive-definite at the design load levels, i.e., if the model is capable of supporting additional load at these levels, then the associated limit states are considered to be satisfied.

There are two principal types of moment transmitting bolted end-plate connections. These are the “flush” and “extended” endplates shown in Fig. 1. In both connections, a plate is shop welded to the beam end and then the complete assembly is bolted on site to the column flange by high strength bolts. The extended end-plate has a higher moment capacity than the flush endplate and is frequently designed as a “full-strength” connection, i.e. with an ultimate moment of resistance at least equal to that of the beam. On the other hand, the flush endplate is often designed as a “pinned” connection in spite of the fact that it can and does transmit significant bending moments. Each of the connection types shown in Fig. 1 demonstrates a wide range of rigidity dependent on various geometrical and material properties embodied in the connection.The flush endplate is currently more popular, especially in portal frame construction, primarily because of its simple fabrication and shipment as the endplate levels with the beam flange.

An algebraic method of moment distribution for the analysis of forces and displacements in redundant structures is presented. The method, described as “synthetic moment distribution”, is originally due to Professor Yu Chao-chung (1957) of National Taiwan University and was published in Chinese in one of the University journals. It appears that the method has not found its way into the western literature. The advantage of the method is that it retains all the features of the standard moment distribution procedure but provides an exact solution with merely one cycle of balance and carryover. An additional feature of the method is that the displacements and rotations of the joints of the structure are also readily obtained, in the spirit of a true displacement method as pointed out recently by Creed (1991). The procedure is illustrated by two examples, one a continuous beam and the other an unsymmetrical portal frame.

The investigation of the design of structural frames to meet a collapse criterion according to rigid-plastic theory leads, under conventional assumptions, to a mathematical model requiring solution by linear programming (LP). However, there are many such different formulations in the literature. The main purpose of this paper is to classify all such methods into four types, each with an associated dual formulation. Relationships between the types of method are also presented and there is a brief discussion of their computational efficiencies and ease of automation.

The resources required for the solution of an optimization problem typically increase with the dimensionality of the problem at a rate which is more than linear. That is, if we double the number of design variables in a problem, the cost of solution will typically more than double. Large problems may also require excessive computer memory allocations. For these reasons we often seek ways of breaking a large optimization problem into a series of smaller problems.

Trusses, i.e. systems of straight, pin-joined bars, may loose their stability in various ways, described in Chapter 1. In particular in plane trusses three kinds of bifurcation may occur (buckling of individual bars or groups of bars; in-plane loss of stability due to additional tension or compression but without buckling of individual bars; out-of-plane loss of stability resembling lateral buckling of high beams), and snap-through is also possible. Analysis of small vibrations imposed on the prebuckling state makes it possible to determine critical loading in any case; however, very often purely static considerations are sufficient. Geometrical non-linearity of the prebuckling state is in most cases essential. Matrix notation is particularly convenient here and the finite element method leads, as a rule, to exact results.