http://www.seipub.org/CE/RSS.aspxen-US2013-07<p class="abstract">Experimental Investigation of Efficiency of Tuned Single and Double Mass Damper and its Application in the Form of an Additional Upper Floor for Seismic Protection of Existing Multistory Buildings</p><ul><li>Pages 15-25</li><li>Author Mikayel Melkumya</li><li>Abstract There are a rather large number of studies on theoretical investigation of behavior of buildings with tuned mass dampers under various impacts. However, the experimental studies in this area are quite limited. This work to a certain extent fills the gap in experimental studies aimed at investigation of behavior of buildings with tuned single and double mass dampers. Based on these investigations different types of dampers were designed and implemented for seismic protection of existing buildings. Linear and non-linear analyses and dynamic tests of these buildings were carried out confirming the efficiency of tuned mass dampers.</li></ul>http://www.seipub.org/ce/PaperInfo.aspx?ID=3757Construction Engineeringhttp://www.seipub.org/ce/PaperInfo.aspx?ID=37572013-07<p class="abstract">Construction Productivity Analysis of Pre-Cast and Conventional Cast-In-Situ Projects</p><ul><li>Pages 26-36</li><li>Author Indra Gunawa</li><li>Abstract Advantages of pre-cast technology in the construction of commercial, residential and institutional buildings are well documented in literature. However, the acceptance of this technology in Malaysia is relatively low with few projects being constructed with pre-cast components. The objectives of this paper are to measure labor productivity in construction, to examine productivity indicators between pre-cast and conventional Cast-In-Situ (CIS) methods, and to explore areas of improvements to promote adoption of pre-cast technology in Malaysia. Data on construction labor productivity are collected using questionnaires, interviews, and observations at the construction sites. Based on statistical analysis performed in this paper, it is concluded that pre-cast method is better than conventional CIS method in terms of construction labor productivity, time to complete a project, variability of construction activities, and loss of efficiency during the construction process. Baseline productivity, unit rates for pre-cast components and correlation of the productivity factors to construction labor productivity are presented as well.</li></ul>http://www.seipub.org/ce/PaperInfo.aspx?ID=2741Construction Engineeringhttp://www.seipub.org/ce/PaperInfo.aspx?ID=27412013-07<p class="abstract">Experimental Investigation on Behavior of SCC Filled Steel Tubular Stub Columns Strengthened with CFRP</p><ul><li>Pages 37-51</li><li>Author Hayder I. AL-SalihNameer A. Alwas</li><li>Abstract In the present research, experimental studies have been devoted to investigating the behavior of self-compacting Concrete Filled Steel Tube (CFST) stub columns strengthened by Carbon Fiber Reinforced Polymer (CFRP) laminates. A total of 28 stub columns under monotonic compression load were tested in order to discover the best configuration of the CFRP for confined column system, fourteen specimens with circular cross-sections (100x300) mm and another fourteen specimens with square cross-sections (100x100x300) mm, and each fourteen specimens can be classified into three categories: three hollow steel tube columns, three plain SCC columns, and eight SCC filled steel tube columns. The experimental results indicated that the use of CFRP laminates to strengthen the CFST has a significant effect on the overall behavior of CFST such as enhancement on its strength and ductility. Also the CFRP confinement delays local buckling of steel tube, prevents a sudden strength reduction caused by the local buckling of the steel tube, and increases lateral confinement of the concrete core. It is found that the best configuration of CFRP tubes system is transverse CFRP tube for circular hollow steel tube columns, circular plain concrete columns, circular concrete filled steel tube columns and square plain concrete column with a percent of increase in ultimate load of (31.1%, 254.3%, 43.4%, and 101%) respectively, and longitudinal CFRP tube for square hollow steel tube columns and square concrete filled steel tube columns with a percent of increase in ultimate load of (30.5% and 25.66%) respectively. While the best configuration of CFRP rings system is four rings of 37.5mm width for both circular and square concrete filled steel tube columns with a percent of increase in ultimate load of (24.15% and 17.1%) respectively.</li></ul>http://www.seipub.org/ce/PaperInfo.aspx?ID=2841Construction Engineeringhttp://www.seipub.org/ce/PaperInfo.aspx?ID=2841