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Amplitude-dependent model updating of masonry buildings undergoing demolition
Panagiotis Martakis,Yves Reuland,Eleni Chatzi 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.27 No.2
Precise knowledge of dynamic characteristics and data-driven inference of material properties of existing buildings are key for assessing their seismic capacity. While dynamic measurements on existing buildings are typically extracted under ambient conditions, masonry, in particular, exhibits nonlinear behavior at already very low shaking amplitudes. This implies that material properties, inferred via data-driven model updating under ambient conditions, may be inappropriate for predicting behavior under seismic actions. In addition, the relative amount of nonlinearity arising from structural behavior and soilstructure interaction are often unknown. In this work, Bayesian model updating is carried out on field measurements that are representative of increasing levels of shaking, as induced during demolition, on a pre-code masonry building. The results demonstrate that masonry buildings exhibit nonlinear behavior as the elastic modulus drops by up to 18% in the so-called equivalent elastic range, in which the observed frequency drop is reversible, prior to any visible sign of damage. The impact of this effect on the seismic assessment of existing structures is investigated via a nonlinear seismic analysis of the examined case study, calibrated under dynamic recordings of varying response amplitude. While limited to a single building, such changes in the inferred material properties results in a significant reduction of the safety factor, in this case by 14%.
오재훈 ( Oh Jae-hoon ),안방율 ( An Bang-yul ) 한국건축시공학회 2019 한국건축시공학회 학술발표대회 논문집 Vol.19 No.1
In the stacking and pitching items of the stone masonry and demolition process presented by 2018's standard of estimate, 7 estimating standards are presented according to the depth of masonry stone, and it is presented that the quantity per unit increases as the depth of masonry stone grows. As a result of analyzing the application status in the site, it is shown that 2 or 3 stones are mainly used according to the stone sizes regardless of the depth of masonry stone, and that as the size of the stone becomes larger, the quantity per unit decreases due to the size per square meter(m2). Also, in most of sites, machine construction is mainly carried out by excavators with clampers attached to them. Therefore, in the 2019's application standard of estimate, it is analyzed that the size is simplified down to 3 sizes reflecting the site application status and that it is revised as a standard reflecting the result that as the stone size becomes bigger, the productivity increases.
Schwerin, Dallas E.,Cavalline, Tara L.,Weggel, David C. Korea Institute of Construction Engineering and Ma 2013 Journal of construction engineering and project ma Vol.3 No.1
Use of recycled aggregates in portland cement concrete (PCC) construction can offer benefits associated with both economy and sustainability. Testing performed to date indicates that recycled brick masonry aggregate (RBMA) can be used as a 100% replacement for conventional coarse aggregate in concrete that exhibits acceptable mechanical properties for use in structural and pavement elements, including satisfactory performance in some durability tests. Recycled brick masonry aggregate concrete (RBMAC) is currently not used in any type of construction in the United States. However, use of RBMAC could become a viable construction strategy as sustainable building practices become the norm. This paper explores the feasibility of use of RBMAC in several types of sustainable construction initiatives, based upon the findings of previous work with RBMAC that incorporates RBMA produced from construction and demolition waste from a case study site. A summary of material properties of RBMAC that will be useful to construction professionals are presented, along with a discussion of advantages and impediments to use. Several quality assurance and quality control techniques that could be incorporated into specifications are identified.