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A detailed finite element (FE) study is presented investigating the factors affecting the failure modes of high strength and stainless steel bolt assemblies under tensile force at ambient and elevated temperatures. Axisymmetric FE models incorporating key behavioural aspects including surface interaction and damage modelling of steel at elevated temperatures were developed. In practice, stripping failure is generally undesired because it results in premature failure of the bolt which can deteriorate rotational capacity of connections and hence compromise the robustness of steel frames. Yet, stripping failure has not been previously investigated in the open literature. In this study, the examined stainless steel bolt assemblies displayed an outstanding ductile response even when stripping failure was observed. Parameters that can govern the failure modes of bolt assemblies at elevated temperatures include the thread length in the grip (L t ), and the relative strength and friction between the mating threads. At ambient temperature, stripping was observed at certain L t lengths depending on the nut dimension deviation from the basic profile. The L t stripping failure threshold reduces with temperature for high strength bolt assemblies while the value fluctuates without a discernible pattern for stainless steel types. Increasing the relative strength and friction coefficient can reduce the L t length threshold, with the former having the greatest influence.

Through the development of an innovative full cross-section tensile testing method, a programme of experiments was conducted to investigate the influence of average cross-section properties on the constitutive relationships for carbon steel, to validate the use of an elastic linear hardening model in practical design, and to assess the resulting accuracy enhancements to the new deformation-based Continuous Strength Method (CSM) of structural steel design. A total of seventeen full cross-section tensile tests on hot-rolled I-sections, hollow sections and cold-formed hollow sections were performed and these were compared with coupon test data obtained from a supplementary programme of fourteen tensile coupon tests and data carefully obtained from the literature. The overall behavioural response of the crosssection tensile tests demonstrated that assuming an elastic, linear hardening material model for the CSM is a reasonable assumption and the previous assumption concerning the magnitude of the strain-hardening modulus, based upon the recommendations of EN 1993-1-5, is overly-conservative. A revised suite of material models was presented and was shown to furnish the CSM capacity equations with a higher degree of accuracy when compared against experimental data.

Currently, 8 out of the 10 most populous megacities in the world are vulnerable to severe earthquake damage, while 6 out of 10 are at risk of being severely affected by tsunami. To mitigate ground shaking and tsunami risks for coastal communities, reliable tools for assessing the effects of these hazards on coastal structures are needed. Methods for assessing the seismic performance of buildings and infrastructure are well established, allowing for seismic risk assessments to be performed with some degree of confidence. In the case of tsunami, structural assessment methodologies are much less developed. This stems partly from a general lack of understanding of tsunami inundation processes and flow interaction with the built environment. This chapter brings together novel numerical and experimental work being carried out at UCL EPICentre and highlights advances made in defining tsunami loads for use in structural analysis, and in the assessment of buildings for tsunami loads. The results of this work, however, demonstrate a conflict in the design targets for seismic versus tsunami-resistant structures, which raise questions on how to provide appropriate building resilience in coastal areas subjected to both these hazards. The Chapter therefore concludes by summarizing studies carried out to assess building response under successive earthquakes and tsunami that are starting to address this question.