Proceedings. 1 st INDONESIAN STRUCTURAL ENGINEERING AND MATERIALS SYMPOSIUM. Department of Civil Engineering Parahyangan Catholic University

ISBN: 978-979-97606-5-4

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The 1st INDONESIAN STRUCTURAL ENGINEERING AND MATERIALS SYMPOSIUM Bandung, November 17-18, 2011

Proceedings

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Department of Civil Engineering Parahyangan Catholic University

Editors : Johannes Adhijoso Tjondro Helmy Hermawan Tjahjanto

The 1st INDONESIAN STRUCTURAL ENGINEERING AND MATERIALS SYMPOSIUM Bandung, November 17-18, 2011

Proceedings

Department of Civil Engineering Parahyangan Catholic University

Editors:

Johannes Adhijoso Tjondro Helmy Hermawan Tjahjanto

The 1st INDONESIAN STRUCTURAL ENGINEERING AND MATERIALS SYMPOSIUM Department of Civil Engineering – Parahyangan Catholic University

KATA PENGANTAR

Indonesian Structural Engineering dan Materials Symposiums (ISEMS) yang diselenggarakan di tahun 2011 ini adalah yang pertama kali diselenggarakan. Direncanakan symposium ini diselenggarakan secara berkala yaitu dua tahun sekali. Symposium ini diselenggarakan atas inisiatif rekan-rekan dosen Jurusan Teknik Sipil Universitas Katolik Parahyangan untuk mewadahi komunikasi ilmiah antar peneliti maupun praktisi teknik struktur dan material. Dunia keilmuan di Indonesia saat ini mengalami dorongan yang kuat akan penelitian dan juga kesadaran para akademisi untuk meneliti meningkat pesat dan kesadaran para praktisi akan perlunya penguasaan ilmunya secara ilmiah juga meningkat pesat. Perancangan teknik saat ini disadari menuntut penguasaan ilmu pada tahap yang lanjut (advanced). Untuk itulah symposium ini dibuat, yaitu mewadahi komunikasi ilmiah antara para akademisi maupun praktisi. Pada symposium yang pertama ini disajikan 32 makalah dari berbagai topik, antara lain, analisis struktur statik dan dinamik, struktur baja, struktur beton, material beton dan lain-lain. Makalah tersebut dibuat oleh akademisi maupun praktisi dari segala penjuru tanah air dan meninjau aspek-aspek ilmiah dari masalah yang dibahas. Publikasi dalam bentuk prosiding ini diharapkan tidak sekedar menjadi sebuah dokumentasi atas makalah yang disajikan, melainkan menjadi rujukan bagi penelitian-penelitian selanjutnya, baik untuk mereka yang hadir maupun mereka yang tidak mendapat kesempatan hadir dalam symposium.

Ketua Panitia Paulus Karta Wijaya

Bandung, 17–18 November 2011

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DAFTAR ISI

Kata Pengantar ..........................................................................................................................................................i Daftar Isi ................................................................................................................................................................. ii

Keynote Papers PERILAKU ELEMEN STRUKTUR BETON BERTULANG BETON BUBUK REAKTIF (REACTIVE POWDER CONCRETE) DENGAN BEBAN LATERAL STATIK MONOTONIK – Prof. Bambang Budiono, Ruddy Kurniawan, Mohammad Junaedy Rahman ............................................................................................ K1–1 PERKEMBANGAN TERKINI TEKNOLOGI MATERIAL BETON HIJAU – Prof. Iswandi Imran, Partogi H Simatupang. ...................................................................................................................................... K2–1

Technical Papers NEXT GENERATION PERFORMANCE–BASED SEISMIC DESIGN: METODE ANALISIS DINAMIK NON–LINEAR UNTUK GEDUNG TINGGI – Davy Sukamta.......................................................................... 1–1 STATUS GEDUNG TINGGI TERBANGUN TERHADAP PERSYARATAN GESER DASAR SEISMIK MINIMUM PADA RSNI 03–1726–201x – Suradjin Sutjipto ............................................................................. 2–1 NEW DEVELOPMENT IN SITE RESPONSE ANALYSIS – Sindhu Rudianto ............................................... 3–1 DAMAGE ASSESSMENT ON BUILDINGS: LESSONS FROM RECENT EARTHQUAKES IN INDONESIA – Herman Parung...................................................................................................................... 4–1 KONSEP PERENCANAAN STRUKTUR PADA DRAFT SNI KAYU 2012 – Johannes Adhijoso Tjondro, Bambang Suryoatmono ........................................................................................................................................ 5–1 NUMERICAL SIMULATION OF CRACK PROPAGATION OF DEAD END ANCHORS OF POST–TENSIONED SUSPENDED SLABS – Elvira, M. Sofi, P. Mendis, D. Baweja...................................... 6–1 ELEMEN STRUKTUR HUBUNGAN BALOK BETON PRATEKAN PARSIAL – KOLOM BETON BERTULANG TAHAN GEMPA YANG HANDAL DAN DAKTAIL PADA SRPMK – M.D. Astawa, I.G.P Raka, Tavio ......................................................................................................................... 7–1 INOVASI PENINGKATAN KINERJA SAMBUNGAN BAUT PADA STRUKTUR BAJA RINGAN YANG MENAHAN MOMEN SEBIDANG – Y. Djoko Setiyarto, Bambang Suryoatmono, Paulus Karta Wijaya............................................................................................................................................. 8–1 PERAN REGEL BAJA DINDING PENYEKAT PADA PENINGKATAN KAPASITAS KOLOM IWF – Sri Tudjono .......................................................................................................................................................... 9–1 ANALISIS KEANDALAN STRUKTUR BAJA DENGAN SIMULASI MONTE CARLO – Dennie Supriatna, Bambang Suryoatmono ........................................................................................................ 10–1 A BREAKTHROUGH ENHANCEMENT OF FINITE ELEMENT METHOD USING KRIGING INTERPOLATION – F.T. Wong....................................................................................................................... 11–1 TEKUK TORSI LATERAL ELASTIS BALOK I DENGAN TUMPUAN LATERAL – Paulus Karta Wijaya........................................................................................................................................... 12–1 EVALUATION OF RAYLEIGH DAMPING IN CANTILEVER BEAM–LIKE STRUCTURE – Dina Rubiana Widarda ....................................................................................................................................... 13–1 Bandung, 17–18 November 2011

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IMPLEMENTATION OF ROTATIONALLY CONSISTENT DIAGONAL MASS MATRICES ON PLATES – Ediansjah Zulkifli, Erik Valentine Bachtiar ............................................................................. 14–1 PENERAPAN METODE ELEMEN BATAS PADA PELAT DI ATAS MEDIUM ELASTIK – Herry Suryadi, Paulus Karta Wijaya .................................................................................................................. 15–1 FINITE ELEMENT MODELING INCORPORATING NON–LINEARITY OF MATERIAL BEHAVIOR BASED ON THE FIB MODEL CODE 2010 – Han Ay Lie, Joko Purnomo .................................................... 16–1 STUDI EKSPERIMENTAL PERILAKU MATERIAL BETON DENGAN VARIASI MATERIAL ABU TERBANG (FLY ASH) DALAM LINGKUNGAN KHLORIDA – Yosefine Ernestine Latupeirissa, Irwan Lie, Jonie Tanijaya ................................................................................................................................... 17–1 PEMANFAATAN SERBUK KACA SEBAGAI POWDER PADA SELF–COMPACTING CONCRETE – Bernardinus Herbudiman, Chandra Januar ........................................................................................................ 18–1 KOMPARASI SIFAT MEKANIK DAN KIMIA KOMPOSIT EPOXY PASIR SILIKA DAN EPOXY SEMEN – Ivindra Z. Pane, Jonbi ....................................................................................................................... 19–1 PRACTICAL EXPERIENCES IN USING HVFA STRUCTURAL CONCRETE – Hadi Rusjanto T., Grace Kurniawati S. ........................................................................................................................................... 20–1 CHLORIDE ION PENETRATION RESISTANCE OF CONCRETES CONTAINING RECYCLED AGGREGATE (RCA) – Kho Pin Verian, Jitendra Jain, Nancy Whiting, Jan Olek .......................................... 21–1 PERILAKU LENTUR BALOK BETON BERTULANG YANG MENGGUNAKAN RECYCLED CONCRETE AGGREGATES (RCA) SEBAGAI ALTERNATIF AGREGAT KASAR – Ashari Ibrahim, Jonie Tanijaya .................................................................................................................................................... 22–1 TINJAUAN TEKNOLOGI JEMBATAN DI INDONESIA – Lanneke Tristanto, Nandang Syamsudin, Redrik Irawan..................................................................................................................................................... 23–1 SISTEM MONITORING KESEHATAN STRUKTUR JEMBATAN SURAMADU – Septinurriandiani, Redrik Irawan, Anton Surviyanto ...................................................................................................................... 24–1 KONSTRUKSI JEMBATAN BALANCED CANTILEVER – PENGATURAN CAMBER DAN DEFLEKSI JEMBATAN – Ida I Dewa G. Wijaya, Iswandi Imran, Tauhid Kurniawan ......................... 25–1 BOND–SLIP CHARACTERISTICS OF BAMBOO REINFORCEMENT FOR STRUCTURAL CONCRETE ELEMENTS – Helmy Hermawan Tjahjanto, Johannes Adhijoso Tjondro.................................. 26–1 BAMBU SEBAGAI BAHAN BANGUNAN MASA DEPAN – Purwito......................................................... 27–1 KUAT TUMPU BAMBU (EMBEDDING STRENGTH OF BAMBOO) – Ali Awaludin, I GL Bagus Eratodi ............................................................................................................................................ 28–1 KUAT LENTUR BALOK LAMINASI–BAUT KAYU INDONESIA – Yosafat Aji Pranata, Bambang Suryoatmono, Johannes Adhijoso Tjondro ........................................................................................ 29–1 FAKTOR STABILITAS BALOK DAN KOLOM KAYU – Bambang Suryoatmono, Bondan Pratama, Maulana Aziz ..................................................................................................................................................... 30–1 THE COMPRESSION STRENGTH OF NAIL–LAMINATED SHORT TIMBER COLUMN – Johannes Adhijoso Tjondro, Fengky.................................................................................................................. 31–1


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DAMAGE ASSESSMENT ON BUILDINGS: LESSONS FROM RECENT EARTHQUAKES IN INDONESIA Herman Parung1 1

Professor, Civil Engineering Department, Hasanudin University, Makassar.

ABSTRAK In the past ten years, Indonesia has experienced several major earthquakes. The large earthquakes have caused not only casualties but also damage to engineered and non-engineered buildings.The paper presents damage assessment on buildings at several locations, namely Nabire (Papua), ToliToli (Central Sulawesi), Banda Aceh and Simeulue (NAD) and Padang (West Sumatera). The assessment shows that most of the damaged buildings have very similar type of damages, and the damages actually could have been avoided by better implementation of design code. The supervision of the building construction on the remote areas has to be improved, because it has been observed that even during the reconstruction of damaged buildings, the new buildings are still vulnerable to new earthquakes. Keywords: damages, supervision, code

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Introduction

In the year 2004, Nabire district of Papua was hit twice by strong earthquakes, namely on 6 February 2004 and on 26 November 2004. Both earthquakes have caused collapsed of buildings and casualties. On Wednesday 20 February 2008, western Sumatera was hit by a shallow major (strong) earthquake with the magnitude of 7.3 on the Richter scale, followed by several smaller earthquakes. Several people witnessed that the earthquake felt in three different directions, namely two horizontal directions and one vertical direction. The total houses damaged were reported 1,350 unit; 455 units were heavily damage while 895 units had light damage (Kompas daily, 23 February 2008). Several buildings near the building under consideration were totally collapse. A one-story house approximately 150 m from the building was totally collapse. Also, a puskesmas building, a police resort under construction and the newly completed Pendopo Kecamatan were collapsed. This fact indicates that the MMI (Modified Mercally Intensity – MMI) in this particular area was high. On September 30, western parts of Sumatera, especially around Padang and Pariaman was also hit an earthquake measured 7.9 on the Richter scale. High number of casualties and buildings collapse (modern and nonengineered) attracted many intention so live coverage on TV screen for several days could be viewed.

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Reports on Damages of Buildings

It can be witnessed from direct observation, that many buildings were partially or completely damaged. The types of damages were common for each area considered in this study. a. Nabire Earthquake: Mesjid Baiturrahman: The mosque was heavily damage in the middle parts (Figure 1), especially in the beams and columns. The weak column strong beam was observed in this building, as shown by damage at the column ends. It could also be observed that several columns were not continuous from the lower to the upper part of the building. Cracks on


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the brickwalls were caused by lack of shear resistance. It could also be concluded that the short-column phenomenon took place due to the addition of walls.

Figure 1.

Damages on Mesjid Baiturrahman

Mesjid Al-Falah: The mosque was totally collapse due to the earthquake (Figure 2). The observation showed that poor connection of reinforcing bars of pedestal columns and upper columns caused the collapse of buildings. It could also be observed that the stiffness of the frame building was not evenly distributed, as shown by unsymmetrical layout of columns. One other possible cause was the absence of torque reinforcing bars for tall beams as used for this building (80 cm high). The column to column spacing was approximately 10 m, the thickness of slab was 15 cm. Grid system of beams was used, but it was difficult to check whether the reinforcing bars were put accordingly.

Figure 2.


Damages on Mesjid Al-Falah

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Gereja Tabernakel: The church experienced very serious structural and non-structural damages. When the earthquake occurred, the building was being renovated. Balcony was being added to the main structure of the cbuilding, in which the beam was connected to the columns by means of short reinforcing bars anchorage. The new configuration of the building caused the change in the resistance of buildings. The columns in the mid-height resist high moments during the earthquake, while initially the moments in the mid-height were low. Poor anchorage of reinforcing bars from the beams balcony caused also the beams to separate from the columns. As can be seen from Figure 3, there were horizontal cracks along the side of the church.

Figure 3.

Gereja Tabernakel

b. Padang Earthquake: Kantor DPD Badan Pembudayaan Kejuangan 45: The building mosque was very badly damage as shown by broken columns at the first floor (Figure 4). As observed, the number of shear reinforcement (stirrup) was insufficient so in the even of stromg earthquake, the induced shear force could not be resisted by the available stirrup. Consequently, concrete spalling was occurred, followed by collapsed of columns. One other reason for the collapse was the insufficient bars splices, which was also observed in Padang area. Three story building: One other building observed shows different type of damage (Figure 5). The three story building was still standing but the middle section of the building sank to the ground. Because the building ccould not be closely observed, it was assumed that there were two possibilities for the damage namely liquefaction caused local settlement of columns in the middle or the columns were broken (less likely). Hotel Bumi Minang: Damage on the Hotel Bumi Minang (Figure 6) was shear failure type, which were observed mainly at the joints. The damages were caused by improper design of joint resistance or by poor construction of joints, so the induced shear forces could not be resisted by the available joints reinforcing bars.


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Figure 4.

Kantor DPD Badan Pembudayaan Kejuangan45

Figure 5.

Three Story Building

Figure 6.


Hotel Bumi Minang

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c. Aceh Earthquake: On Wednesday 20 February 2008, Simeulue Island in Sumatera was hit by a shallow major (strong) earthquake with the magnitude range 7.3 on the Richter scale, followed by several smaller earthquakes. Several people witnessed that the earthquake felt in three different directions, namely two horizontal directions and one vertical direction. A one-story house approximately 150 m from the market building is totally collapse. Also, a puskesmas building, a police resort under construction and the newly completed Pendopo Kecamatan (Subdistrict Residence) are collapsed. This fact indicates that the MMI (Modified Mercally Intensity – MMI) in this particular area is high. A 2 story building (Figure 7) was currently under construction when the earthquake hit, and most of the structural components have been completed. After the earthquake, it was reported that the structure is damage. The overall stability of the structure was still maintained although there were damages on the columns and beams. There was no permanent horizontal deformation to either major direction of the buildings. This can also be confirmed by the fact that the roof truss and the metal roofs do not experience any damage or fall down. Formation of plastic hinges at beam ends and column bases comply with the design code requirement (SNI, page 50), which is called capacity design (strong column weak beam).

Figure 7.

Two Story Building

Plastic hinges (cracks), as sign of the earthquake energy dissipation, formed at column bases. There were also small cracks at upper end of the ground floor columns. Columns at the upper floor are in good condition, except diagonal cracks at two beam-column joints. The absence of 2-3 stirrups (hoops) at two particular columns just under the beam-column joints has resulted in the concrete spalling (crushing) during the earthquake. This is due to high shear stress caused by the seismic excitation, which should have been resisted by the shear reinforcement (hoops/stirrups). After the concrete crushed, eventual load is carried only by the steel so they bent. Most of beams cracked at the beam ends, which indicate the formation of plastic hinges as energy dissipation mechanism. Some cracks are large, but the other cracks are smaller (hair cracks). For the assessment purpose, most of the beam with large cracks was destroyed with hammer in order to check the depth of cracks. The construction of the roofs was almost completed. Some workers were working at the roof when the earthquake hit. There is no single roof fall down, and the roof truss is also still in good condition. Parts of the bricks already constructed totally collapse, including the brick walls at the second floor at the seaside. The interior brick walls under construction, which have not been yet connected to tie beam or practical column, is also damage. Separation of brick walls of the toilette at the ground floor from the main structure is also noted. Parts of the falling bricks are totally separated from the mortar.


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3.

Similarities of Damages

As can be observed from several different areas of Indonesia, there are several damages which are common found in the event of strong earthquake. The most common failure is the collapse of brick walls, even after moderate earthquake. This can be attributed to lack of confinement, which is usually supplied by the so-called practical columns. Failure at the column bases due to interruption of reinforcing bars of the foundation to column is also found. As can be seen from the previous photo, it is common in the less prone region to cut the reinforcing bars of the foundation just above the ground. After the foundation is completed, the reinforcing bars are simply connected to the reinforcing bars of columns by means of wire. In case of earthquake, cyclic loading will easily cause the reinforcing bars of the foundation and the columns to separate which later will result in concrete spalling and eventually collapse of the structure. In the Nabire earthquake, several mosques and churches experienced similar damages. Additional construction of structural elements such as balcony and curve beams which were directly attached to the column approximately at the mid-height, caused the change in the stiffness configuration. The mid-height which was originally designed to have low moments will be forced to resist higher moments. Cracks at the beam column joints were also observed at several buildings. Placing stirrup at the core of the joints is considered time consuming and difficult by some workers, so they tend to avoid placing the rebar in this area. Most shear reinforcing bars will be placed just outside the column face. In the event of strong earthquake, absence of just one stirrup at the joint area could cause damage, as shown in the event of Aceh earthquake.

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Concluding Remarks

The damages on buildings as described shows that if a structure designed to resist forces less than the actual force, there is potential damage to the building. Good design if not followed in the field, such as deleting stirrup around the joint, will also cause the same problem. In order to reduce the potential impact of earthquake, all relevant parties should take own responsibility. All design should be prepared by certified engineer, and the authority should issue building license only if administrative and technical aspects are fulfilled. If considered necessary, random site inspection should be carried out by the authority to ensure that all buildings are constructed in accordance with the approved documents. To this task, the staff should also has the qualification and power to carry out the checking. It is also need to be addressed that the main principle of the earthquake resistant design is the strong column weak beam concept. It means that damages only allowed in the beams, and not in the columns. Reduction of the effective area of column due to placement of plumbing pipes in the columns, very common in Makassar area, should be avoided. Other practice that can be seen in Makassar is the concreting of columns using manual mixer, while the beams and slab using ready mix concrete. With this practice, it cannot be guaranteed that the strength of the concrete columns will be higher than the beams. The number of steel frames built in Makasar areas is steadily increase due to the ease of erection. However, there is also potential risk because the strength of the steel concrete composite beams is underestimated. The design engineer should consider that the plastic moment capacity of composite frame is much higher than the plastic moment capacity of steel beam so the determination of the column section should be based on the composite beam capacity. The lack of knowledge among the design engineer or worker in the remote areas of Indonesia should also be considered. Training or workshop should be organized either by government body or professional association in order to reduce mistakes in the design or construction phases. It is hoped that if this particular area can be improved, the number of casualties or buildings damages can be reduced significantly.


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5.

References

1) Department of Public Works (PU) of Indonesia. Guide lines for repairing of building after an earthquake, (kumpulan brosur, kliping dll) 2) EERI (Earthquake Engineering Research Institute). Post-Earthquake Investigation Guideline, California, USA 3) Parung, H. (1999). Seismic Resistance of Composite Structures, Konferensi Nasional Rekayasa Kegempaan,. Bandung: 4) Parung, H. (2003). Test on Composite Beam-Column Sub-Assemblages, Jurnal Hi-Tech, Edisi O1/Tahun V, Fakultas Teknik Unhas

5) Penelis and Kappos Works. Earthquake Resistant Concrete Structures


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Proceedings. 1 st INDONESIAN STRUCTURAL ENGINEERING AND MATERIALS SYMPOSIUM. Department of Civil Engineering Parahyangan Catholic University

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