Numerical comparison on the efficiency of conventional and hybrid buckling-restrained braces for seismic protection of short-to-mid-rise steel buildings

Buckling-restrained brace (BRB) is a specific kind of bracing system which has an acceptable energy dissipation behavior in a way that would not be buckled in compression forces. However, considerable residual deformations are noticed in strong ground motions as a result of the low post-yield stiffness of the BRBs. The seismic performance of a modern lateral load resisting system, which is called the hybrid BRB, and its conventional counterpart are assessed and compared in this paper. Multiple plates with different stress–strain behavior are used in the core of this new innovative system, and this is its difference with the existent BRBs. Nonlinear static and incremental dynamic analyses are carried out for three building frames with different structural heights, which use conventional and hybrid BRB systems. To carry out response history analyses, the FEMA P695 far-field earthquake record set was adopted in different hazard levels. The hybrid BRBs are shown to have superior seismic performance in comparison with the conventional systems based on the response modification factor and the damage measures including residual displacements and inter-story drift ratios

The exact and approximate conditional spectra in the multi-seismic-sources regions

The exact and two approximate conditional spectra are compared in this manuscript as a target spectrum for the purpose of ground motion selection. The considered site is a real offshore site located at South Pars Gas Field in the Persian Gulf region. This case study site is influenced by four major seismic area sources in which the deaggregation results confirm that many comparable seismic scenarios can be taken into account. Therefore, an alternative to the conventional approximate conditional spectrum is proposed that has a small deviation from the exact solution. In addition, the use of different conditioning status of the probabilistic seismic hazard deaggregation (i.e., occurrence versus exceedance of the target spectral acceleration) for calculating the exact distribution of conditional spectrum was investigated. The results show that one of the proposed approximate approaches leads to conditional distributions which provide acceptable agreement with those obtained from the exact solution

Developer Dynamics and Syntactic Quality of Commit Messages in OSS Projects

Part 2: OSS Projects ValidityInternational audienceCommunity dynamics play an important role in the Open Source Software (OSS) development paradigm. Researchers have extensively studied the human aspects of the OSS paradigm from the point of view of community formation to community evolution. A few studies relate community dynamics with OSS product attributes such as code quality. However, the impact of community dynamics on non-code contributions such as commits has not been explored. In this paper, the aim is to analyze the impact of community dynamics on syntactic quality of commit messages of an OSS project. We first propose and validate a commit message quality model, and then use that model to analyze the OSS projects. Empirical analysis of seven OSS projects available in the Git repository shows that a small group of contributors active at the same time in a project leads to high syntactic quality contributions. These observations may prove useful to developers as well as project managers who need quantifiable techniques for monitoring the OSS projects