Common Structural Details and Deficiencies in Indonesian RC Buildings: Preliminary Report on Field Investigation in Padang City, West Sumatra

Significant damage to reinforced concrete buildings by the 2009 Western Sumatera Earthquake revealed that deficiencies in design engineering and/or construction practice existed. This indicated that enforcement of building design codes was lacking. The Indonesian government has updated the building design codes which should have been applied in the construction of new buildings. However, enforcement of these codes on design engineering and/or construction practice in Padang city is not clear. In this study, a field investigation was performed to investigate common structural details and deficiencies in newly constructed multi-story reinforced concrete buildings. The investigation was conducted through visiting building construction sites in Padang city area. This study preliminary reports the investigation results on 39 private buildings and 8 government buildings. The common deficiencies found on the investigated buildings were low material quality, small structural dimensions with light longitudinal reinforcement, insufficient transverse reinforcement with poor details, improper location of lap splice of rebar, lack of hoops inside exterior and interior beam-column joints, and deficient anchorage of beam reinforcement to exterior beam-column joints. These investigation results clarify that enforcement of the latest buildings design codes in design engineering and/or construction practice is still lacking in the investigated area

Metoda Evaluasi Kapasitas Seismik Gedung Beton Bertulang Eksisting dengan Aplikasi Model Dinding Bata

Abstrak. Sebuah metoda dikembangkan untuk mengevaluasi kapasitas seismik gedung beton bertulang eksisting dengan mengaplikasikan sebuah model strut diagonal untuk memperhitungkan pengaruh dinding bata dalam struktur rangka. Dalam model ini lebar strut diagonal diberikan sebagai fungsi tinggi kontak antara dinding dan struktur rangka yang dapat diselesaikan dengan persamaan kesetimbangan tegangan tekan dan perpindahan lateral pada daerah kontak. Kekuatan dan kekakuan lateral dinding didapatkan berdasarkan lebar strut diagonal. Model strut diagonal telah diverifikasi dengan hasil pengujian struktur rangka dengan dinding bata. Didapatkan hasil yang sesuai antara pengujian struktur dan hasil analisis model untuk kekakuan dan kekuatan lateral serta duktilitas dinding bata. Oleh karena itu, model strut diagonal dapat diaplikasikan untuk mengevaluasi kapasitas seismik gedung beton bertulang eksisting di kota Padang. Dalam penelitian ini dievaluasi kapasitas seismik sebuah gedung beton bertulang 2 (dua) lantai untuk tanpa dan dengan memperhitungkan pengaruh dinding bata dengan mengaplikasikan model diagonal strut untuk dinding bata. Sedangkan kapasitas seismik gedung tanpa pengaruh dinding bata dihievaluasi berdasarkan standar Jepang. Sebagai hasilnya didapat bahwa dinding bata dalam struktur rangka dapat meningkatkan kapasitas seismik gedung beton bertulang secara siknifikan.Abstract. A method for evaluating the seismic capacity of existing reinforced concrete (R/C) building was developed by implementing a diagonal strut model for considering brick infill effects. In this model, the strut width is presented as a function of frame-infill contact length, which was evaluated by static equilibriums related to compression balance and lateral displacement compatibility at the frame-infill interfaces. The lateral strength and stiffness of infill were obtained based on the strut width. The strut model has been verified through comparison with  experimental results of a brick masonry infilled R/C frame. Good agreements were observed between the experimental and analytical performance on the lateral strength and ductility of the infill. Consequently, the diagonal strut model can be an effective tool for precisely screening earthquake-vulnerable existing R/C buildings in Padang city. In this study, two calculations of seismic capacity of two stories existing R/C building, without and with considering brick infill effects, were conducted by applying the diagonal strut model. However, the seismic capacity of R/C building  without infill effect was evaluated based on Japanese standard. Consequently, it reveals that the brick infill significantly affected the seismic resistances of the investigated building

MODELING OF BRICK MASONRY INFILL AND APPLICATION TO ANALYSES OF INDONESIAN R/C FRAME BUILDINGS

The Thirteenth East Asia-Pacific Conference on Structural Engineering and Construction (EASEC-13), September 11-13, 2013, Sapporo, Japan

Studi Eksperimental tentang Pengaruh Dinding Bata Merah Terhadap Ketahanan Lateral Struktur Beton Bertulang

Abstrak. Bata merah umum digunakan sebagai dinding pada struktur bangunan beton bertulang di negara berkembang dan rawan bencana gempa bumi seperti Indonesia. Dalam proses prencanaan, dinding bata merah biasanya diperlakukan sebagai komponen non-struktur, dimana interkasi antara dinding dan struktur beton bertulang diabaikan. Fakta hasil observasi lapangan pasca bencana gempa bumi Sumatera Barat menunjukkan bahwa dinding bata merah dapat membantu mengurangi kerentanan struktur beton bertulang yang dikenai beban lateral. Dalam makalah ini, hasil serangkaian pengujian laboratorium struktur portal beton bertulang akan dibahas untuk menentukan pengaruh dinding bata merah terhadap ketahanan lateral struktur beton bertulang. Hasil pengujian menunjukkan bahwa dinding bata mempunyai pengaruh yang signifikan terhadap ketahanan lateral struktur beton bertulang. Peningkatan ketahanan lateral juga diperoleh dengan penggunaan ukuran bata merah yang lebih besar dan penggunaan plesteran pada kedua sisi dinding.Abstract. Reinforced-Concrete (R/C) frame structures with unreinforced clay brick masonry (URM) infill walls are commonly used in developing countries with regions of high seismicity. The walls are usually treated as non-structural components, and their interaction with the bounding frames is often ignored in designing process. Field evidences after West Sumatera earthquake have shown that URM infill walls can help reduce the vulnerability of the R/C frame structures against lateral load. In the present paper, it is an attempt to highlight the series laboratory experimental results of the R/C frame structures with URM infill walls. Results of the experimental studies which have indicated URM infill walls can have a significant influence on the lateral resistance of the R/C frame structures. Increasing the lateral resistance is also observed on the R/C frame structures uses larger size of the clay brick masonry and uses mortar on the infill walls' surfaces

Modeling of Brick Masonry Infill for Seismic Performance Evaluation of RC Frame Buildings

豊橋技術科学大

Pengaruh Dinding Bata dengan Bukaan (Lobang) terhadap Ketahanan Lateral Struktur Rangka Beton Bertulang

AbstrakMakalah ini menjelaskan serangkaian pengujian pada struktur rangka beton bertulang dengan dinding bata penuh dan dinding bata ada bukaan (lobang) untuk mengetahui konstribusi dinding bata ada bukaan terhadap kekuatan lateral struktur beton bertulang. Empat benda uji struktur rangka beton bertulang dan dinding bata dengan skala 1:4, yaitu satu benda uji struktur rangka tanpa dinding pengisi dan tiga struktur rangka dengan dinding bata, diuji dengan memberikan beban lateral (beban dorong) pada bagian atas balok struktur hingga benda uji mengalami keruntuhan (pushover). Besarnya perpindahan lateral direkam selama pengujian untuk mengontrol peningkatan beban lateral. Retak dan perkembangannya diobservasi selama pengujian untuk mengidentifikasi mekanisme keruntuhan benda uji. Hasil pengujian menunjukan bahwa keruntuhan benda uji didahului dengan keruntuhan pada dinding bata sebelum keruntuhan struktur kolom. Kekuatan dan kekakuan lateral struktur rangka dengan dinding pengisi lebih besar daripada kekuatan dan kekakuan struktur rangka tanpa dinding pengisi. Struktur rangka dengan dinding bata penuh memiliki kekuatan lateral lebih dari dua kali kekuatan lateral struktur rangka tanpa dinding. Dinding bata dengan satu bukaan di tengah seluas 40% dan dinding bata dengan dua bukaan seluas 25% meningkatkan kekuatan lateral struktur rangka beton bertulang masing-masing sebesar 25% dan 47% .AbstractThis paper presents the series of experimental tests of reinforced-concrete (R/C) frame structures infilled with solid brick wall and opening brick walls to evaluate contributions of brick infills with openings to lateral strength of RC frames. Four 1/4-scale single story and single bay RC frame specimens, one bare frame and three infilled frames, were tested by applying the static monotonic lateral load to the upper beam of specimens. During the testing, lateral displacements of infilled structure were monitored to control the incremental lateral loads. The cracks, crack propagation and major cracks were observed throughout the tests to identify the mechanism failure of specimens. As the results, failure of brick wall was prior to the failure of RC columns. The lateral strength and stiffness of infilled frames were always higher than those of bare frame. The solid brick infill significantly increases the lateral strength of overall RC frame more than two times. The brick infill with a center opening of size 40% and the brick infill with 2 (two) openings of size 25% increase the lateral strength of R/C frame by about 25% and 47%, respectively

Cyclic behavior of the R/C frames with reinforced masonry infills

This study focuses on the experimental works to define the behavior of the reinforced concrete (R/C) frame model with the strengthening of the brick masonry infill by using the embedded reinforcement bars subjected to lateral reversed cyclic loads. A previous study by applying the lateral monotonic static loads showed that the embedded reinforcement bars increased the lateral capacity of the R/C frame and also delayed the failure of the brick masonry infill and R/C frame structure as well. However, in order to define its seismic capacity, a lateral reversed cyclic loading is required. The experimental works in this study were conducted by preparing and testing the 1/4 scaled-down R/C frame specimens represented the first story of the middle multi-story commonly constructed in the earthquake-prone area such as West Sumatera, Indonesia. The R/C frame specimens were two R/C frames with brick masonry infills where one of them strengthened by the embedded reinforced bars. All specimens were tested for applying the lateral reversed cyclic loads. The applied lateral load, the lateral displacement, the progressive cracks, and the failure mode of the specimens were observed and recorded during experimental works. As it was expected, the presence of the embedded reinforced bars in the brick masonry infills increases the seismic capacity and stiffness of the R/C specimens and also delayed the failure of the specimens. The experimental results in this study imply the simple strengthening method for the brick masonry infills

Cyclic behavior of the R/C frames with reinforced masonry infills

This study focuses on the experimental works to define the behavior of the reinforced concrete (R/C) frame model with the strengthening of the brick masonry infill by using the embedded reinforcement bars subjected to lateral reversed cyclic loads. A previous study by applying the lateral monotonic static loads showed that the embedded reinforcement bars increased the lateral capacity of the R/C frame and also delayed the failure of the brick masonry infill and R/C frame structure as well. However, in order to define its seismic capacity, a lateral reversed cyclic loading is required. The experimental works in this study were conducted by preparing and testing the 1/4 scaled-down R/C frame specimens represented the first story of the middle multi-story commonly constructed in the earthquake-prone area such as West Sumatera, Indonesia. The R/C frame specimens were two R/C frames with brick masonry infills where one of them strengthened by the embedded reinforced bars. All specimens were tested for applying the lateral reversed cyclic loads. The applied lateral load, the lateral displacement, the progressive cracks, and the failure mode of the specimens were observed and recorded during experimental works. As it was expected, the presence of the embedded reinforced bars in the brick masonry infills increases the seismic capacity and stiffness of the R/C specimens and also delayed the failure of the specimens. The experimental results in this study imply the simple strengthening method for the brick masonry infills

A Simple Strengthening Method for Preventing Collapsed of Vulnerable Masonry Infills

A series of structural tests were conducted to examine the seismic performance of masonry infills strengthened with particular materials on infilled reinforced concrete (RC) frame structures. Six 1:4 scaled-down RC frame specimens had been prepared, including one brick-infilled frame without strengthening and five brick infills strengthened with innovative strengthening materials. The materials were steel wire mesh, chicken hexagonal wire mesh, plastic wire mesh, fiber-reinforced polymer (FRP), and plastic stretch film. The strengthening was diagonally applied on both surfaces of the masonry infill. The steel wire mesh, chicken hexagonal wire mesh, and plastic wire mesh were sewn using steel wire, while the FRP sheet was glued using epoxy resin and the plastic stretch film was glued using synthetic rubber adhesive. The specimens were tested following the FEMA 461 standard testing protocol, which involved applying lateral static cyclic loading to the specimens. The displacement transducer apparatus measured the deformations of the specimens, and crack propagation was observed during experimental works. The experimental results showed that most specimens exhibited an increase in their lateral strength, secant stiffness, deformation capacity, and energy dissipation. Among all prepared specimens, the specimen using plastic stretch film showed the best and most promising results, i.e., long deformation and steady lateral strength after yielding. This result suggests that using plastic stretch for strengthening can increase ductility performance. It is expected to withstand earthquake shaking, has low application costs, and is feasible for application even by unskilled local laborers