Experimental Tests for Pre-Qualification of a Set of Buckling-Restrained Braces

Buckling restrained braces are increasingly used as structural fuse elements due to their stable and quasi-symmetric cyclic behaviour and capacity to dissipate a large amount of energy. However, a wider adoption of buckling restrained braced frames is often precluded by the proprietary character of most buckling restrained braces, need for their experimental qualification and sometimes lack of experience of designers. To overcome these problems, a set of typical buckling restrained braces were developed in view of their pre-qualification. Both "conventional" and "dry" devices were considered, with capacities corresponding to typical steel multistorey buildings in Romania. Detailing of buckling restrained braces aimed at investigating the core aspect ratio, gap size, strength of the buckling restraining mechanism, and the unbonding material. The paper presents the results of the experimental program, and recommended design parameters of qualified specimens.

Development of a Seismic Design Approach for Infill Walls Equipped with Structural Fuse

Presented herein is a seismic design approach developed for a proposed infill wall “structural fuse” system for use in building frames. The purpose of this system is to prevent damage to frame or infill walls due to infill wall-frame in-teraction during potentially damaging earthquakes by isolating them through a “sacrificial” component or a structural fuse. The design approach includes a procedure for design and application of the fuse system in a multi-bay, multi-story build-ing with moment resisting frames. The empirical equation developed to predict the in-plane strength of masonry infill walls equipped with structural fuse is discussed. A calculation method is suggested to specify an appropriate fuse element capacity arrangement in a building frame in order to achieve desirable and controlled structural performance. The design procedure is shown through application to two buildings used for example, a low-rise (4-story) and a mid-rise (8-story) building. The result of the study demonstrates that the proposed isolation system has merits and can potentially improve the seismic performance of masonry infill walls by protecting the infill wall and the frame from damages due to their in-teraction.

Differential Burst Pressure of Marine Pipelines as an Independent Layer of Protection

Offshore pipelines and risers are designed to different codes leading to different reliability targets, and different wall thicknesses. Pipeline design codes also differentiate between areas where people are present and those with no population or less environmentally sensitive. As a result, the offshore section of the pipeline (with “thinner walls”) could be considered to work as a structural fuse during an unforeseen pressure surge; if the pipeline bursts first, then the occupants of platform would be exposed to less risk than if the riser or pipeline in the vicinity of the platform were to fail. This implies that differential burst pressure could act as an Independent Protection Layer (IPL). This paper explores conditions that sections of a pipeline must satisfy in order to be considered as an IPL. A first order reliability method is outlined for determining the required target reliability. The application of this approach is described in a case study.