Konuralp Girgin

Performance Evaluation of a Strengthened Building Considering the Soil-Structure Interaction

In this article, performance evaluations of a 3D building strengthened by additional shear-walls are presented as a case study by considering the foundation effects. Soil-structure interaction is included in the nonlinear static analysis of the building and performance evaluations are made according to Chs. 6 and 8 of FEMA440. Different foundation types such as mat foundation, continuous or single footings are considered in the analysis. Tensionless elastic-plastic Winkler soil model is used for soil behavior. Non-linear push-over analysis and performance evaluations are obtained by SAP2000 computer package. Elastic-plastic Winkler soil behavior is represented by equivalent frame elements subjected only to axial forces and equivalent axial stiffness is defined for these elements. Mat foundation and footings are idealized as linear-elastic thick shell elements in the analysis. Performance evaluations and comparisons for the strengthened building are given in detail for different foundation types.

Simplified formulations for the determination of rotational spring constants in rigid spread footings resting on tensionless soil

AbstractIn spread footings, the rotational spring constants, which represent the soil-structure interaction, play an important role in the structural analysis and design. To assign the behaviour of soil, which is generally represented via Winkler-type tensionless springs, necessitates time consuming iterative computing procedures in practice. In this study, a straightforward approach is proposed for the soil-structure interaction of rigid spread footings especially subjected to excessive eccentric loading. By considering the uplift of footing, the rotational spring constants of those type footings under axial load and biaxial bending are easily attained through the proposed simplified formulations. Since these formulations enable manual calculation, iterative computer efforts are not required. The formulations under consideration can be applicable to symmetric and non-symmetric rigid spread footings. The numerical results of this study are verified with SAP2000.

The Seismic Performance Evaluation of An Eccentrically Braced Steel Frame by Non-Linear Analyses

Bu calismada, Deprem Bolgelerinde Yapilacak Binalar Hakkinda Yonetmelik-2007 (DBYBHY-2007) ye gore boyutlandirilan alti katli dis merkez caprazli bir celik perdenin deprem performansi, zaman tanim alaninda dogrusal olmayan hesap yontemi kullanilarak degerlendirilmistir. Bu degerlendirmede goreli kat otelemeleri, kat kesme kuvvetleri, capraz ve kolonlarin ic kuvvet istemleri ile bag kirisi kesme kuvveti ve donme istemleri dikkate alinmistir. Zaman tanim alaninda dogrusal olmayan analizler yedi adet deprem ivme kaydi kullanilarak gerceklestirilmistir. Analizler sonucu elde edilen istemlerin ortalama degerleri esas alinarak dis merkez caprazli celik perdelerin kullanildigi orta yukseklikteki binalar icin DBYBHY-2007’de ongorulen kapasite tasarimi yaklasiminin yeterliligi arastirilmistir. The goal of this paper is to investigate the non-linear response and to assess the seismic performance of a six story eccentrically braced steel frame (EBF). For this, split-K-braced EBF with high ductility level designed according to the Turkish Earthquake Code-2007 (TEC-07) is analyzed under seven selected earthquake records. The performance of the EBF is assessed considering drift, story and base shear demands, brace and column axial forces and bending moment demands, link beam shear force and rotation demands. Mean values of the demands are used in the performance assessment. The provisions based on capacity design approach specified in TEC-07 for EBFs with high ductility level are discussed by employing the findings..

A Simplified Solution of the Torsional Rigidity of the Composite Beams by Using FEM

In this paper, the torsional rigidity of the composite sections formed by different materials is obtained by using a finite element procedure. In the derivation of the differential equation, the Saint-Venants stress function was used. The obtained partial differential equation was discretized by finite elements to get the potentials in the nodal points. After the calculations of the unknown potentials on the composite cross-section, the torsional rigidity is calculated by integrating the potentials on the solution domain. To test the validity of the proposed algorithm, the available analytical and numerical results from the previous studies were studied. It was seen that this new algorithm is efficient and simpler than the previous ones.