Effects of masonry infill walls with different opening configurations on seismic behavior of long-span gravity-load-designed RC frames | |
| Author | Surasak Niyompanitpatana |
| Call Number | AIT Diss. no.ST-17-01 |
| Subject(s) | Earthquake resistant design Concrete masonry Buildings--Earthquake effects |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Structural Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. ST-17-01 |
| Abstract | Post-earthquake disaster surveys, laboratory experiments, and computer simulations have revealed the poor seismic performance of gravity-load-designed (GLD) buildings with masonry infill walls. Frame-infill interaction can result in highly complex behavior with unexpected and undesired effects during ground motion at both global and local levels. To numerically analyze masonry walls, a fully infilled wall panel can conventionally be represented by two compression-only equivalent struts, located along the diagonals of the panel, connecting one corner to another corner. However, this conventional strut design is derived from the experimental result of a fully infilled frame with a low aspect ratio of bay width to clear story height at about 1.0, and may not apply to infilled frames with high aspect ratios, particularly those with openings. Furthermore, most previous studies on frame-infill interaction were limited to frames with low to moderate aspect ratios (≤ 2). Many existing GLD buildings are constructed with infilled reinforced concrete (RC) frames with a high aspect ratio (> 2.0), and some are schools and hospitals. Thus, further experimental studies are required for infilled frames with high aspect ratios. To improve understanding regarding the seismic behavior of these infilled frames, a comprehensive experimental study was conducted. Five half-scale models of long-span GLD RC frames representing typical school buildings in Thailand with aspect ratios of 2.7, single-bay, single-story, and various configurations of masonry infill walls were used as specimens and tested under quasi-static cyclic loading. Results revealed that infill walls, either with or without openings, greatly modified the global cyclic response behavior of the frame by significantly increasing lateral stiffness, lateral strength, and energy dissipation while altering the hysteretic behavior. However, the degree of this modification and the interaction mechanism between the infill wall and the surrounding frame varied greatly from case to case. Briefly, a fully infilled wall behaved like two inclined compression-only struts, but their characteristics were quite different from conventional diagonal struts. An infill wall a partial height substantially modified the response behavior of the frame by restraining the lateral displacement in the lower half of the columns, allowing them to deform only in their upper half portion. An infill wall with a central opening behaved like two separated walls, where each wall actively interacted with the frame only when was pushed by the frame. Furthermore, infill walls with side openings behaved like one strut, actively engaging only when the frame pushed the wall, thus creating unsymmetrical cyclic force-deformation behavior of the infilled frame. Available simple analytical models were also employed to predict the behavior of infilled frames. Results revealed that for fully infilled walls, the conventional single strut model (as recommended by FEMA356, NZSEE, CCMPA, and MSJC) could not predict the infilled frame behavior with an acceptable degree of accuracy at both global and particularly local levels. For an infill wall with openings (or partial infill), the single strut model modified by a reduction factor (recommended by NZSEE), or the multi-spring model (Mostafaei and Kabeyasawa, 2004) predicted infilled frame behavior in some cases. To overcome the limitations of these models, some modifications were performed which led to the development of the proposed double strut model. However, these modifications retained model simplicity for use in real applications. |
| Year | 2017 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. ST-17-01 |
| Type | Dissertation |
| School | School of Engineering and Technology |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Pennung Warnitchai; |
| Examination Committee(s) | Punchet Thammarak;Anwar, Navee;Nakano, Yoshiaki.; |
| Scholarship Donor(s) | Ubon Ratchathani Rajabhat University; |
| Degree | Thesis (Ph. D.) - Asian Institute of Technology, 2017 |