Research on Engineering Structures and Materials

197-206

Authors: Melik Ziya Yakut, Sinem Esen

In this study; based on energy-efficient design parameters, the effects of building design parameters on the energy consumption of the building were examined. Accordingly, a reference building has been created as an example of application in the hot-humid climate zone. In the process of modelling the building, BIM (Building Information Modelling) software Autodesk Revit was used. The model has been transferred to Green Building Studio (GBS) for energy performance analysis and evaluation of design alternatives. The parameters evaluated in terms of energy consumption of the building were selected from among the design alternatives produced by GBS, based on energy-efficient design parameters. As a result of the energy performance analysis of the reference building via GBS, the building's annual electricity consumption is 35,137 kWh and the annual fuel consumption is 93,729 MJ. Based on the evaluation of selected design parameters as a result of reference building energy performance analysis; HVAC systems have been found to have the most impact on energy consumption (rates of changes; 36.83% in annual electricity consumption, 90.27% in annual fuel consumption). HVAC systems, selected to be highly efficient and suitable for climate type, have the potential to save significant energy in the amount of energy consumption throughout the life cycle. In addition to this, as of the early design phase, the energy efficient design of the building is of great importance in terms of a holistic evaluation and maximum energy efficiency.

229-240

Authors: Hayri Baytan Ozmen, Mehmet Inel, Yunus Demirtas

Soft story irregularity is one of the main reasons of the building damage during past earthquakes and has been mentioned in almost all reconnaissance reports. Soft story due to increased story height is a recognized subject but soft story may also arise due to abrupt changes in amount of infill walls between stories, which are usually not considered as a part of load bearing system. This study investigates soft story behavior due to increased story height, lack of load bearing infill walls at ground story and existence of both cases using nonlinear static and dynamic response history analyses. Mid-rise reinforced concrete buildings are considered due to their high portion in existing building stock. Displacement capacities at Immediate Occupancy, Life Safety and Collapse Prevention performance levels and story drift demands of the regular and soft story models are determined. Soft story behavior due to change in story height and/or infill amount is evaluated in view of displacement capacities, drift demands and structural behavior. It is observed that, soft story due to infill walls may be as damaging as soft story due to increased story height.

257-269

Authors: Fatoş Koç, Selay Sert Çok, Nilay Gizli

In this study, silica aerogels were produced by two-step sol-gel method to investigate the effect of pH on the physical, chemical and textural structure of aerogels. Tetraethyl orthosilicate (TEOS) used as a silica source. (3-aminopropyl) triethoxysilane (APTES) acted as a silica co-precursor. The quantity of sol precursors kept constant through the experiments and the pH of hydrolysis and condensation reactions were varied. As a result of the experimental studies, the optimum pH values to achieve monolithic aerogel were obtained when the pH of hydrolysis is 3 and the pH of condensation is 10. Physical, chemical and morphological characteristics of the samples were examined by performing FTIR and SEM and density analyses. Results showed that the sample SG-pH3/7 had also well-defined porous structure with homogenous pore distribution, a stable lightweight and monolithic form.

283-292

Authors: Ekrem Altuncu, Recep Akyüz

Automobile brake disc are subjected to cyclic thermal, mechanical and corrosive effects. In general, gray cast iron grades are preferred as disc brake materials. Lamellar cast iron disc brakes have a limited lifetime and are replaced periodically during the maintenance-service process. With the growing interest in the number of Battery Electric Vehicles (BEV), there is a need for disc brake with longer service life on discs. Therefore, in the automotive sector, in line with increasing competition and user demands, there is an interest in new coating types and materials with corrosion free properties, a longer service life and high brake performance. Wear and corrosion resistant plasma spray coatings are the key to increasing the service life and braking performance of cast iron discs. In this study, the discs (GG20) are coated with Alumina- Titania based ceramic material by atmospheric plasma spray method. The ceramic coated disc brakes were installed on the road driving test vehicle and disc brake thickness reduction were measured periodically according to wear test plan throughout 20.000 km. The test results show that the ceramic coating provides 18 times more wear resistance compared to uncoated disc brake. In addition, coated disc brakes exhibited superior performance in corrosion tests. As a result of the investigations carried out on disc brakes, it is understood that plasma spray ceramic coatings can be used alternatively in brake disc systems.