scope:

Objectives and Scope

In this study state-of-the-art analytical methods of predicting inelastic behavior of braced structures are reviewed and assessed by comparing experimental and analytical results. The study is an analytical follow-up to experimental investigations on inelastic brace and braced frame behavior reported in References 2 and 3. The objectives of this study are to assess the capabilities of available analytical models for predicting such inelastic responses, and to improve the understanding of the inelastic response of braced structures.

First a brief review of existing post-buckling brace models is made in Chapter 2. Their developmental basis, inter-relationships, applicabilities and limitations are examined in detail. The basic considerations, member parameters and deformations affecting brace inelastic behavior are also identified. A representative brace model is chosen for implementation in frame analyses and verified in Chapter 3 against recently available experimental data [3]. The choice of parameters for the model is based on the results of individual brace tests [2]. Brace model parameters are selected to cover a reasonable range of slenderness ratios for offshore applications. The analytical model's performance in predicting the experimental behavior of X-braced tubular steel towers is evaluated in Chapter 4, and the limitations of the models are examined. Suggestions for improved frame and brace modeling are offered. In Chapter 5 experimental data is interpreted to obtain an improved relationship controling the deterioration of buckling load with inelastic cycling. A new model based on a physical representation of a buckling brace is proposed. This model may overcome some of the limitations of available models. Conclusions and recommendations for future research are offered in Chapter 5.