The second paper, "Characterization and Implementation of ADAS Type Hystertic Damping Device in Steel Structure" by U K Koshtri, A B Patel and S P Purohit, examines the effect of added damping and added stiffness on steel structures. Seismic performance on use of metallic damper on a nine-story moment-resistant frame has been examined. It has been realized that steel structures perform better than any other structure during seismic excitations due to inbuilt material ductility. During some earthquakes, it was discovered that material ductility alone is not enough to ensure ductile behavior in steel structures. Structures rely heavily on their post-elastic behavior to survive during severe ground shakings. Here the capacity of the frame system to quickly dissipate energy while enduring massive inelastic deformation is critical for the survival of the structure. Thus passive energy dissipation system, which is economical and efficient, has been developed. Many times, metallic damper in design use is Added Damping and Added Stiffness (ADAS), which consists of X-shaped steel plates. These flexure yielding types ADAS dampers have proved quite suitable in structures to increase seismic performance. General parameters for ADAS type metallic dampers are stiffness ratio, B/D ratio and ratio of restoring forces. All these parameters are assumed to be between 1.5 and 2.0. Stiffness ratio is expressed as ratio of stiffness of structures and combined stiffness of bracing and damper. B/D ratio is ratio of stiffness of damper and bracing. With these parameters, stiffness of damper is decided from equations developed by researchers. In this study, three types of dampers with constant height, width, thickness and different numbers of plates are examined. The nine-story building is modeled in SAP2000 software using M1 model developed by Krawinkler and others. For the model, first three modes of free vibration are studied. Then the model is analyzed with addition of damper. El Centro earthquake records are used as seismic excitation forces to determine various study parameters. The results show that by installing an X-plate ADAS metallic damper into a steel portal frame, the SAP2000 software reactivity can be decreased by 30 to 50%. Thus use of ADAS improves damping qualities and boosts overall structural rigidity.

The last paper, "Bagasse Ash as Partial Cement Replacement Material: An Evaluation" by Chala Basha Chawaka, Habtamu Fekadu Gemeda, Amanuel Diriba Irena, Boki Tamiru Tola and Abdi Biranu, examines the effect of partial replacement of cement through sugarcane Bagasse Ash (BA) in concrete preparation. Sugarcane BA is a byproduct of fuel blending in the sugar industry. The disposal of this waste product in agriculture causes environmental problem. Hence this study, deals with partial replacement of cement with sugarcane BA in concrete preparation. First, all physical properties, such as density, fineness and particle size of sugarcane bagasse, are determined. Studies have shown that sugarcane BA has a higher surface area and a lower density than cement. Control concrete samples are made with ordinary portland cement of Dangote brand. Typical river sand with specific gravity of 2.6 and a particle size below 4.75 mm are used. Available crushed rock is used as coarse aggregate of size 20 mm. BA ranging from 5% to 20% by weight is used to replace the cement in preparation of test concrete. The cast specimen, either cylinder or beams, does not show cohesivness and shows lots of voids. Various test specimen casts are tested at interval of 7, 14, 21 and 28 days, respectively. The result shows that ordinary Portland cement has a larger density than BA. Generally, concrete with BA has greater water absorption than control concrete. The study concludes that up to 5% of cement can be successfully replaced with BA, and with this replacement, high concrete characterisctics are achieved as compared to control concrete. The study also found that up to 10% of cement can be replaced with bagasses ash with equivalent properties, but any higher replacement will have a drop in characteristics performance.