Challenge Journal of Structural Mechanics

1-8

Authors: A. Ghani Razaqpur, Francesco Bencardino, Lidia Rizzuti, Giuseppe Spadea

The capacity provisions of conventional Reinforced Concrete (RC) and Prestressed Concrete (PC) beams subjected to combined action of torsion, shear and flexure are well known and stated by international/national codes. Similar provisions lack for concrete members containing Fibre Reinforced Polymer (FRP) reinforcements. In general, there is paucity of research on the treatment of torsion combined with other stress resultants for FRP-RC/PC members. In this paper the theoretical method proposed by the Canadian standard CSA S806 for FRP-RC/PC structures is presented. The critical issues, related to this topic, such as the appropriate strength and inclination of the diagonal struts and failure criteria are critically analyzed and addressed. In order to assess the reliability of this study a comparison between available experimental data regarding FRP-RC/PC beams subjected to combined actions and their corresponding theoretical provisions derived by the CSA S806 standard is shown. Furthermore, another approach, available in literature, which is based on the space truss model, is examined and used for comparison in order to evaluate the theoretical provisions offered by this model against the tests value of the set of the beams analyzed in this study. Based on the critical analysis of the results, it can be highlighted that the CSA method is able to conservatively predict the capacity of these beams.

13-17

Authors: Hisato Hotta, Takeshi Nakajima

Partial walls separated from columns are generally treated as nonstructural elements because their behavior aren’t analyzed much. Partial walls jointed rigidly to RC frames raise horizontal load-carrying capacity, however they may give an influence on RC frames when they fall in brittle failure. Objective of this paper is to clarify the influence of partial walls falling in shear failure on RC frames through a static loading test and a shaking table test. The experiment shows that, after one of the partial walls fails, story drift rapidly increases. It shows progress of flexural deformation at one end of columns, and it may cause story collapse. The result is obtained from both loading tests.

22-26

Authors: Farzad Hejazi, Jamalodin Noorzaei, Abang Abdullah Abang Ali, Mohd Saleh Jaafar

Various types of interlocking mortarless (dry-stacked) block masonry systems have been developed worldwide. However, the characteristics of dry joints under compressive load, and their effect on the overall behavior of the interlocking mortarless system, are still not well understood. This paper presents an investigation into the dry-joint contact behavior of masonry and the behavior of interlocking mortarless hollow blocks wall construction subjected to seismic excitation. In the system developed, the blocks are stacked on one another and three-dimensional interlocking protrusions are provided in the blocks to integrate the blocks into walls. The response of the mortarless hollow block wall with respect to acceleration displacement and stress have been discussed.

32-37

Authors: Turgut Öztürk, Zübeyde Öztürk, Onur Öztürk

Earthquakes are one of the most important and hazardous natural disasters in the world and in our country. They also have lots of characteristics from the point of effects caused by them. For this reason it requires special engineering approach to analyze those effects and to design earthquake resistant structures. Almost all of the life losses caused by the earthquakes are related with improperly designed buildings safety of which are not ensured against severe earthquakes. Structural damages and collapses cause very important economical losses. So, understanding of the characteristics of an earthquake and correct determination of the behavior of buildings under earthquake excitation turn out to be the most important requirement to build earthquake resistant buildings. When we take into consideration the destructive effects of severe earthquakes that happened especially in recent years (Kocaeli 1999, Düzce 1999) one can easily see the importance of knowing the behavior of buildings under earthquake loads. In this study torsional effects that occur during earthquake excitations are analyzed in multi-story reinforced concrete buildings. In that manner the behavior of reinforced concrete structures under earthquake loads are examined and by the way the behaviors of structures having torsional irregularities are enlightened and clarified. Moreover the effects of rigidity, ultimate capacity and ductility on the behavior of structures under ground motion are summarized. Torsional irregularity is a key irregularity in determination of the method to be used in earthquake analysis. Definition of the torsional irregularity of a multi-story reinforced concrete building is explained in accordance with Turkish Earthquake Code and the related principles of computations that have to be followed according to the code are given. Multi-story reinforced concrete buildings are classified according to their plan geometry and the effects of plan geometry on the torsional irregularity are explained. While in certain structures torsional irregularity may happen in very high levels in some structures it may happen so small that can be safely omitted. For that reason buildings forming torsional irregularity are classified and their characteristics and torsional irregularity parameters are given. Shear walls without causing any torsional irregularity on buildings having different plan geometries are shown.