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Kondisi tanah yang berada pada lahan yang miring dan tidak rata berpotensi membahayakan bangunan yang berada di sekitar lahan tanah tersebut, terlebih bilakemiringan lahan cukup curam. Oleh karena itu perlu dilakukan upaya penanggulangan untuk mengatasipermasalahan tersebut, salah satunya dengan cara membuat talud dinding penahan tanah. Sistemdinding penahan tanah berundak, dapat menjadi salah satu cara untuk mengurangikecuraman sudut lereng sehinggameminimalisir terjadinya longsor. Kondisi demikian juga dilakukan pada lereng yang terletak di sebelah bangunan Mushola Baitussalam, Dusun Tegalsale Desa Jembrak,Kecamatan Pabelan Kabupaten Semarang. Talud dinding penahan tanah bangunan MusholaBaitussalam berada pada elevasi tanah yang lebih tinggi dari pada jalan raya. Selain itu, terdapat parit, selokan dengan aliran air yang cukup deras. Oleh karena itu diperlukan dinding penahan tanah tambahan untuk mencegah longsor. Kemungkinan adanya gerusan akibat aliran air paritselokan cukup berbahaya bagi struktur bangunan mushola sehingga memerlukan penanganansegera agar struktur bangunan mushola terhindar dari keruntuhan akibat adanya gerusan air danketidakstabilan lereng tanah.Tim Pengabdian kepada Masyarakat Departemen Teknik Sipil UNDIP membantu masyarakat menanganipermasalahan tersebut dengan memberikan pendampingan pembuatan talud dinding penahantanah yang sesuai dengan kondisi bangunan mushola Baitussalam. Kerjasama dan koordinasiyang baik antara Tim Pengabdian kepada Masyarakat Departemen Teknik Sipil UNDIP bersama-samadengan warga Dusun Tegalsale, Desa Jembrak berjalan dengan baik sehingga permasalahan masyarakat mengenai tanah di bangunan MusholaBaitussalam tersebut dapat tertangani dengan tuntas.Struktur talud dinding penahan tanah dibuat dari pasangan batu kalidengan betondiatasnya sebagai pengikat keseluruhandinding penahan tanah tersebut (capping beam). Dinding talud dibuat berundak-undak dan adanya paritselokan di sisi bangunan mushola Baitussalam dirapikan serta dibuat saluran air agar tidakmenyebabkan erosi/kikisan pada tumit (toe) dinding talud.Kata kunci : talud, longsor, dinding penahan tanah, batu kali, capping beam

Jalan merupakan infrastruktur penting bagi pergerakan manusia dan merupakan akses penghubung antar wilayah. Infrastruktur jalan yang baik akan membuat pengguna jalan lebih nyaman dan mudah untuk berpindah dari tempat yang satu ke tempat yang lain. Kondisi jalan yang baik akan membawa dampak yang menguntungkan dari sisi ekonomi bagi kemajuan suatu daerah. Kondisi jalan penghubung antar desa di wilayah Desa Jembrak saat ini masih banyak yang memprihatinkan. Terdapat ruas jalan yang saat ini masih berupa jalan tanah berbatu dimana menjadi akses yang harus dilalui oleh masyarakat Desa Jembrak menuju desa tetangga. Kondisi tersebut semakin parah saat memasuki musim penghujan, dimana jalan tanah akan menjadi becek bahkan licin saat dilalui. Hal inilah yang menjadi alasan dilakukannya Pengabdian Masyarakat di Desa Jembrak. Kegiatan pengabdian kepada masyarakat ini dilakukan oleh Tim Pengabdian Masyarakat Departemen Teknik Sipil Universitas Diponegoro kepada masyarakat Desa Jembrak untuk bersama-sama dan bergotong-royong membuat jalan penghubung desa dengan material beton. Struktur beton dipilih untuk pembuatan jalan desa karena sumber material utama yaitu pasir dan split mudah didapatkan di Desa Jembrak. Potensi tenaga dan semangat gotong royong penduduk desa juga masih sangat tinggi. Pengabdian kepada Masyarakat di Desa Jembrak ini berupa pendampingan pembuatan jalan yang terdiri dari metode pencampuran beton, tahapan pelaksanaan, hingga perawatan beton secara benar dengan masyarakat sebagai tenaga pelaksana pekerjaan pembuatan jalan. Sehingga, dengan adanya kerjasama yang baik antara Tim Pengabdian Masyarakat Departemen Teknik Sipil Universitas Diponegoro dan warga Desa Jembrak, jalan penghubung desa dari rabat beton yang layak guna memperlancar mobilitas masyarakat Desa Jembrak dapat terwujud.Kata kunci : jalan beton, mobilitas, pembuatan jalan

Site-specific ground motion analysis is a method for developing surface ground motion and surface spectral acceleration models. The analysis is performed by conducting propagation analysis from base-rock to surface elevation. The important information needs for site-specific ground motion analysis is the position of base-rock or bedrock below the surface level. This paper presents the investigation results of base-rock elevation at the Diponegoro University Semarang, Indonesia. The background reason for the base-rock investigation of this university area is because this area is located close to three seismic sources (Semarang, Lasem and Demak shallow crustal faults). Seismic microzonation caused by all three seismic source scenarios are still on-going. One of the important analysis used for seismic microzonation at the study area is site-specific ground motion analysis. The base-rock elevation prediction in the study area was performed using a combination of single and array microtremor tests and soil boring investigations. The base-rock elevation prediction developed using microtremor tests was verified using the soil profile developed from soil boring investigation. Based on soil boring and microtremor investigations, the base-rock elevation at the university area was predicted at 30 to 60 m below the surface level.

SNI 1726:2012 states that surface spectral accelerations S MS (0.2 second) and S M1 (1 second) can be calculated by multiplying site factors Fa (0.2 second) and Fv (1 second) with spectral accelerations S S (0.2 second) dan S 1 (1 second). All site factors used by SNI 1726:2012 are adopted from ASCE/SEI 7-10. In 2013 Stewart and Seyhan proposed new and different site factors compared to ASCE/SEI 7-10. These site factors are then used for developing ASCE/SEI 7-16 with minor improvement for site class SE (soft soil). ASCE/SEI 7-16 states that the site factors for site class SE with S S greater than 1g or S 1 greater than 0.2g, shall be calculated using Site Specific Analysis (SSA). The SSA method used for calculating site factor is difficult for ASCE/SEI 7-16 to be implemented in Indonesia. This paper describes the result of S MS and S M1 study at five cities (Jakarta, Bandung, Semarang, Yogyakarta and Surabaya) for site class SC, SD and SE using site factors proposed by Stewart and Seyhan and site factor SNI 1726:2012. The S MS and S M1 at five cities calculated using site factors proposed by Stewart and Seyhan are ±15% differences compared to S MS and S M1 calculated usingSNI 1726:2012 site factors.

Site soil classification provides vital information for predicting the soil amplification or the site factor. The site factor is important for calculating the surface spectral acceleration in the seismic design of buildings. Based on the Indonesian seismic code, site soil classification can be conducted by calculating the average standard penetration (N-SPT) resistance, the average shear wave velocity (VS) and the average undrained soil strength (Su) of the upper 30 m of a subsoil layer. Different results may be obtained at the same location when the site soil classification is predicted using N-SPT than when using VS data. The restriction of N-SPT values until a maximum of 60 compared to a VS maximum of 750 m/sec can produce different soil classes and will directly impact the calculation of the surface spectral acceleration. This paper describes the different results of site soil classification prediction calculated using the average N-SPT and the average VS, conducted at Semarang City, Indonesia. Site soil classification maps developed based on both datasets are also presented, to evaluate the different site soil classification distributions. Only soil classes SD and SE were observed using N-SPT maximum 60, whereas soil classes SC, SD and SE were observed using N-SPT maximum 120.

Indonesia has followed development of new seismic design criteria in the new seismic building codes, from hazard-based in the former SNI-03-1726-2002 to the current risk-based SNI-1726-2012. The major changes in SNI-1726-2012 are using Risk-Targeted Maximum Considered Earthquake (MCER) Spectral Response Acceleration maps. Five years later (2017), the seismic hazard maps have been updated adopting the most recent data and current state of knowledge in probabilistic and deterministic seismic hazard assessment methodologies. To establish the New 2019 Risk Targeted Ground Motion (RTGM) of spectral acceleration (Ss and S1), and risk coefficients (CRS and CR1), for both short (T=0.2s) and 1-second (T=1s) periods, respectively have been developed based on the 2017 Indonesian hazard maps. The RTGM was calculated as the spectral value resulting in 1% probability of building collapse in 50 years through numerical integration of hazard curves and structural capacity. The log-normal standard deviation (?) of the structural capacity envelope has been revised from 0.70 to 0.65. This paper presents the new resulted RTGM maps. Furthermore, the paper also presents revision of seismic amplification factors for 0, 0.2, and 1 second periods (FPGA, Fa, and, Fv) to generate ground surface maximum and design spectra associated with the siteclassifications.

Balok baja kastela adalah profil baja yang dikembangkan dari profil I yang dipotong bagian badan dan disambung lagi sedemikian rupa sehingga membentuk lubang pada bagian badan. Bentuk lubang profil balok baja kastela pada umumnya adalah persegi enam (heksagonal). Pembuatan balok baja kastela perlu memperhatikan jarak antar lubang agar balok mempunyai kemampuan menahan beban tertinggi. Tulisan ini menyajikan hasil penelitian untuk menentukan jarak antar lubang yang optimum pada balok baja kastela dengan mempertimbangkan distribusi tegangan, deformasi, dan kelelehan pada balok tersebut. Penelitian diawali dengan perhitungan menggunakan metode Elemen Elemen Hingga (Finite Element Method /FEM) kemudian dilanjut dengan pengujian di laboratorium. FEM dilakukan untuk menentukan ukuran dan jarak antar lubang optimum pada balok kastela. Variasi sudut bukaan lubang dilakukan antara 45o sampai 70o. Hasil analisa FEM kemudian diujikan di laboratorium dengan ukuran dan jarak antar lubang optimum untuk mengevaluasi perbedaan hasilnya. Hasil penelitian menunjukkan lubang profil dengan kemiringan antara 45o sampai 70o sebaiknya dibuat dengan jarak antar lubang antara 0.1 sampai 0.25 dari tinggi profil balok kastela dengan distribusi lubang terbaik adalah antara 5 sampai 7 lubang per meter.

This study discusses the size and distance optimization of hexagonal holes in castellated steel beams. The optimization study of castellated steel beams was performed using finite element method (FEM). The results of optimization analysis are then verified by implementing laboratory tested of 225 mm height castellated steel beam specimens. The specimens were modified from 150 mm height IWF section profile. The model of castellated steel beams is divided into six different variation models which represent 45, 50, 55, 60, 65 and 70 opening angle of hexagonal holes. All castellated steel beam models have 150 mm vertical height holes ( ho ) and each holes are separated with equal distance varies from 0.042 ho to 3.153 ho . The results of FEM analysis indicate that the strength of castellated steel beams increase with a factor of 1.938 to 2.041 compare to 150 mm IWF original profile. The optimum results from FEM analysis was a castellated steel beam that has 60 angle size with the optimum hole distance was 0.186 ho to 0.266 ho . Comparison analysis of laboratory test results and FEM analysis results indicated that the difference between those two approaches are not more than 1.011 with COV (coefficient of variation) value 0.069.

Ahmad Yani International Airport is located in Semarang (the Capital City of Central Java Province) Indonesia. The airport was first operated on June 6 2018 and designed it using 2012 Indonesian Seismic Code (SNI 1726:2012 in Seismic resistance design codes for building and other structures, Jakarta, pp 1–138, [16]). The airport was commercially operated one year after the new Indonesian Seismic Hazard Maps 2017 released (ISHM-2017). The most important information obtained from ISHM-2017 is the new predicted seismic source located close to the airport area. This paper expresses the seismic hazard analysis (SHA) of the airport area based on the new ISHM-2017. The analysis is performed by conducting three basic SHA steps such as the Probabilistic and Deterministic Seismic Hazard Analysis (PSHA and DSHA), a combination of PSHA and DSHA for developing Most Considered Earthquake Risk (MCER) spectral acceleration and the final analysis is related with the calculation of surface spectral acceleration for developing design spectral acceleration (DSA). The new DSA is then compared to the previous DSA developed based on SNI 1726:2012 (SNI 1726:2012 in Seismic resistance design codes for building and other structures, Jakarta, pp 1–138, [16]) and also compared to the surface spectral acceleration developed using site response analysis (SRA). The result of the study shows that the new DSA has no significant differences and improvements compared to the previous DSA (SNI 1726:2012 in Seismic resistance design codes for building and other structures, Jakarta, pp 1–138, [16]) and SRA results.

Research and development of Indonesian Seismic Hazard Maps in 2017 (IHSM-2017) have a direct impact on the development of seismic resistance code for building design in Indonesia. The development of new Indonesian seismic code for building and non-building design is still on-going, following the development of ASCE/SEI 7-16. This paper describes the development of design acceleration response spectrum (DARS) for building design. DARS-2019 is developed following the same method describes in the Indonesian seismic code [9] and ASCE/SEI 7-16. The study for developing DARS-2019 was performed at 35 cities in Central Java and Yogyakarta Provinces, Indonesia. A comparative study with 2012 seismic code (DARS-2012) was also performed in this study to evaluate the improvement of the DARS at those 35 cities. The analysis was performed for three different site soil classes (hard soil/SC, medium soil/SD and soft soil/SE). The purpose of this study is to evaluate the direct impact of the new ISHM-2017 on DARS-2019. Based on the analysis conducted at 35 cities, the improvement of DARS-2019 compared to DARS-2012 for site classes SC, SD and SE are less than 0.1 g except for site class SC at five cities located close to Opak fault trace.

Spectral acceleration and acceleration time histories are the two seismic loads generally used for dynamic analysis of a building. The structural design of buildings is implemented using spectral acceleration at the ground surface obtained from the national seismic code. However, acceleration time histories are developed from specific earthquake events and implemented for building evaluation. This paper presents building evaluations of three existing buildings located in Semarang with heights of at least 40 m. The buildings were built on three different soil types, that is, hard, medium and soft soils. The evaluation was performed by conducting two component north-south and east-west directions of acceleration time histories modified from Semarang fault earthquake scenarios having a magnitude of 7 Mw and maximum epicentre distance 15 Km. Due to incomplete data on Semarang fault earthquakes, the acceleration time histories incorporated herein were collected from worldwide earthquake data bases and modified using response spectral matching and seismic propagation analysis. Stability analyses in terms of structural deformation and drift ratio were carried out for the three buildings. The results show that all three buildings have the capability to resists earthquakes up to a maximum magnitude of 6.5 Mw with an epicentre distance of over 5 Km.

Today, water requirements are not analogously with its availability. Therefore, build water reservoir dam is one of the simple concepts for fulfilling water requirements. Embankment dam is one of the most popular dam build in Indonesia. Stability of embankment dam should be taken into account to evaluate the safety condition in retaining water. Safety against seepage is one of the most important steps for checking the possibility of failure of embankment dam. PLAXIS is alternative software that can be used for evaluating safety of embankment dam due to seepage condition. This paper explains the study of pore water pressure and seepage effects against Sermo Dam safety using PLAXIS and compares it with field measurement data from piezometer and V-Notch monitoring. The study was conducted during dam operational conditions. The analysis was carried out using Mohr-Coulomb model to calculate discharge of seepage and settlement. The value of pore water pressures within the model, upstream and downstream, positions are then reviewed with the real dam. The results of model analysis shows that the more higher water level within the dam reservoir the more higher pore water pressure will be happened that affects in increasing discharge of seepage and settlement of dam.

Research on seismic, microzonation of Semarang is still ongoing. Following the research conducted by Team for Revision of Hazard Maps of Indonesia 2010, Lasem fault was the only fault that should be taken into account for seismic mitigation of Semarang. New research conducted by Team for Updating of Seismic Hazard Maps of Indonesia 2016 suggesting four new and closest shallow crustal fault sources (Rawapening, Weleri, Demak and Semarang Faults) which should be taken into account for seismic hazard mitigation of this city. Those four new seismic sources are typical reverse mechanism seismic sources. However Lasem fault is a typical strike slip mechanism seismic source. This paper presents the development of surface acceleration time histories due to three shallow crustal fault (Lasem, Semarang and Demak) earthquake sources with average magnitude 6.5 Mw. This research was performed by implementing de-aggregation hazard analysis, response spectral matching and site response analysis to obtain modified acceleration time histories. The modified acceleration time histories were developed due to inadequate data caused by those three fault sources. Surface acceleration time histories were calculated at 288 boring locations and then separated into three different time histories based on site class soil conditions (hard, medium and soft soil classes).

Fault is one of the dangerous earthquake sources that can cause building failure. A lot of buildings were collapsed caused by Yogyakarta (2006) and Pidie (2016) fault source earthquakes with maximum magnitude 6.4 Mw. Following the research conducted by Team for Revision of Seismic Hazard Maps of Indonesia 2010 and 2016, Lasem, Demak and Semarang faults are three closest earthquake sources surrounding Semarang. The ground motion from those three earthquake sources should be taken into account for structural design and evaluation. Most of tall buildings, with minimum 40 meter high, in Semarang were designed and constructed following the 2002 and 2012 Indonesian Seismic Code. This paper presents the result of sensitivity analysis research with emphasis on the prediction of deformation and inter-story drift of existing tall building within the city against fault earthquakes. The analysis was performed by conducting dynamic structural analysis of 8 (eight) tall buildings using modified acceleration time histories. The modified acceleration time histories were calculated for three fault earthquakes with magnitude from 6 Mw to 7 Mw. The modified acceleration time histories were implemented due to inadequate time histories data caused by those three fault earthquakes. Sensitivity analysis of building against earthquake can be predicted by evaluating surface response spectra calculated using seismic code and surface response spectra calculated from acceleration time histories from a specific earthquake event. If surface response spectra calculated using seismic code is greater than surface response spectra calculated from acceleration time histories the structure will stable enough to resist the earthquake force.Fault is one of the dangerous earthquake sources that can cause building failure. A lot of buildings were collapsed caused by Yogyakarta (2006) and Pidie (2016) fault source earthquakes with maximum magnitude 6.4 Mw. Following the research conducted by Team for Revision of Seismic Hazard Maps of Indonesia 2010 and 2016, Lasem, Demak and Semarang faults are three closest earthquake sources surrounding Semarang. The ground motion from those three earthquake sources should be taken into account for structural design and evaluation. Most of tall buildings, with minimum 40 meter high, in Semarang were designed and constructed following the 2002 and 2012 Indonesian Seismic Code. This paper presents the result of sensitivity analysis research with emphasis on the prediction of deformation and inter-story drift of existing tall building within the city against fault earthquakes. The analysis was performed by conducting dynamic structural analysis of 8 (eight) tall buildings using modified acceleration time histor...

The shear wave propagation analysis (SPA) is a method for developing surface ground motion and spectral acceleration by conducting seismic wave propagation from bedrock to surface elevation. The bedrock elevation and soil profile from bedrock through surface elevation are important information needed for SPA. The shear wave velocity, damping ratio, soil density and shear modulus are the four parameters that are needed for developing SPA. This paper describes a modified SPA for developing surface ground motion and spectral acceleration by conducting two different soil deposit model, actual and modified bedrock elevation models. The difference in the two models depends on the bedrock elevation used for SPA. The actual bedrock elevation model is conducted based on the real bedrock elevation observed using microtremor test. However, the second model is performed based on the final depth of soil boring investigation. The study was conducted at the Engineering Faculty of Diponegoro University. Based on the microtremor observation, the bedrock elevation was predicted at 50 metres below the surface level. However, two soil boring investigations conducted in this study area were stopped at 30 metres below the surface level. The surface ground motion and spectral acceleration developed from both models are almost equal.

Research on the improvement of Indonesian seismic hazard maps has already been carried out by the National Center for Earthquake Studies in 2017. One important global data obtained from this research related with all earthquake sources mechanism which might be used for building design and evaluation. Based on this research there are two important and closest earthquake sources to Semarang, Lasem fault (strike slip mechanism) and Semarang fault (reverse mechanism). This paper presents the dynamic structural evaluations of the hospital building (approximately 49 meters height) located in Semarang, Indonesia, by conducting two seismic load functions, two-component surface spectral acceleration (X and Y directions) developed from Indonesian Seismic Code SNI:1726-2012 and three-component (North-South, East-West and Vertical) of surface acceleration time histories. All acceleration time histories were modified from three earthquake events which represents Semarang fault earthquake scenarios and developed from earthquake events with magnitude from 6.3 to 6.9 Mw and the maximum distance of building to earthquake epicentre 15 Km. Based on the floor deformation and the drift ratio results calculated using dynamic analysis, the building is predicted has the capability on resisting earthquake scenarios up to a maximum magnitude 7 Mw with minimum epicentre distance 10 Km.

On the dams, there are many parameters may change and be different from design. Therefore, it is necessary to analyse the parameters so that it can comply with conditions in the field. By knowing the material parameters can foresee events in the future during operational condition of dam. It is because material parameters can influence behaviour of the structure. Displacement, one aspect in failure of dam, is considered due to its function to accommodate design of camber in dam crest and provide early warning system. Displacement behaviour is related to material parameters in term of Young’s modulus and Poisson ratio. Nevertheless, difficulties for testing material in the dam make approach method to analysis material parameters are required. One of them is done by numerical simulation. In this study, the review of displacement is in the core zone at different elevations and different water level conditions. Value of material parameters which influence displacement were determined using back analysis method. Then, it could be analysed displacement result between modelling and monitoring instrumentation using Settlement Gauge. Results show good agreement trend between those displacement’s results. Moreover, the displacement’s value from simulation model analysis is greater than Settlement Gauge.

Seismic microzonation study of Semarang is still on-going following the recommendations from the Team for Revision of Seismic Hazard Maps of Indonesia 2010 (TRSHMI-2010). The study was performed by carrying one-dimensional site response analysis at 190 locations and implementing Lasem fault as a closest seimic source that significantly influence the hazard of the city. The analysis was performed using two soil deposit models, 30 m and real soil deposit models, to get ground surface peak acceleration (PGA) and amplification factor of PGA. The results obtained using the first model are then compared with the results obtained using the second model. To perform the analysis bedrock elevation and acceleration time histories data are needed. The bedrock elevation was estimated based on 218 single station seismometer measurements. Five different time histories representing different earthquakes with magnitude 6.5 MW and maximum distance 20 km are collected from worldwide historical earthquake records. The results of this study includes the distribution of surface PGA and amplification factor of PGA. The PGA and amplification factor calculated using 30 meter soil deposit model are greater than the same values calculated using real soil deposit model.

An expansive clay is soil material that is composed of various minerals include kaolinite, montmorillonite and illite group. Mineral montmorilinite have the sensitivity to the effects of the water is very easy to swell and shrink. High and low levels of swelling and shrinkage (shrinkage) expansive clay is determined by the high and low content of montmorillonite on expansive clay granules. Because of these properties are very high content of montmorillonite often cause problems in the building. This study uses a solution of Soda Api (NaOH) as a stabilizer through the compaction process Modified Proctor on (OMC + 7,5%) Proctor standard by the number of collisions each - each is 10 x, 25x and 56x, and the amount of additional water on weight soil dry , with variations in increments of water by 95% : 5% NaOH, water by 90%: 10% NaOH and water by 85% : 15% NaOH. This research was conducted testing - testing in the laboratory include: Index properties, Swelling Pressure, Swelling Potential and CBR with curing and no curing. Results - results in these tests show that the value of the property index showed an increase, Test UCS showed an decrease, Test CBR by soaking at the age of 7 days with a mixture of caustic soda 10% showed the best results, while the pressure test expands and Test Potential expands decreased significant.

Development of surface acceleration time histories is important for dynamic analysis of structure design and evaluation. Acceleration time histories usually developed from seismograph records due to specific earthquake event. Following the research conducted by Team for Revision of Seismic Hazard Maps of Indonesia 2010 and 2016, Lasem fault and Semarang fault are two closest and dangerous shallow crustal fault earthquake sources which must be taken into account for seismic mitigation of Semarang. This paper presents the development two components surface acceleration time histories for Semarang caused by Semarang fault earthquake scenarios, with magnitude from 6 Mw to 7 Mw and maximum epicentre distance 15 Km. This research was performed by conducting deterministic hazard analysis, response spectral matching and site response analysis to obtain a pair of modified acceleration time histories. Site response analysis was performed by conducting 30 meters soil deposit model by taking the assumption that the position of bedrock elevation is 30 meters below the surface layer. Modified acceleration time histories were developed from a pair time histories (North-South/NS and East-West/EW direction) collected from worldwide historical earthquakes. Modified time histories were developed due to limited time histories data caused by Semarang fault earthquake source.

Research on seismic microzonation of Semarang is still ongoing. The first seismic microzonation research for this area was performed on 2015. Seismic microzonation map was developed by implementing deterministic 1-D site response analysis at 190 boring locations. Lasem fault was considered to be the main earthquake source which taken into account for seismic microzonation research of Semarang. The second research for developing seismic microzonation map was performed on 2016. Following the research conducted by Team for Updating Seismic Hazard Maps of Indonesia 2016, Rawapening Fault, Ungaran Fault, Weleri Fault, Demak Fault and Semarang Fault are five new shallow crustal fault earthquake sources identified in this research. This paper presents the development of seismic risk microzonation map caused by Semarang fault earthquake scenarios with maximum 6.9 Mw. Deterministic 1-D site response analysis was performed at 288 boring locations for developing seismic risk microzonation map. This research was performed by implementing response spectral matching and site propagation analysis. Due to inadequate data caused by Semarang fault earthquake, response spectral matching was implemented in this research to obtain modified acceleration time histories. All acceleration time histories were developed from five different earthquakes with magnitude 6.05 – 6.9 Mw and maximum epicentre distance 15 Km.

Dam assessment under a specific earthquake event is one of the most important approaches to dam evaluation. The assessments are usually performed by running two different models of seismic loads: spectral acceleration and acceleration time histories. The first model is implemented using seismic load information developed from a national code. The second approach is implemented using earthquake scenarios by conducting acceleration time histories. The National Center for Earthquake Studies 2017 suggested that a shallow crustal fault and subduction are the two most dangerous seismic sources of Yogyakarta Province. This paper presents an evaluation of Sermo dam in terms of dam displacement and peak ground acceleration (PGA) under the Java subduction source earthquake scenarios. The evaluation was performed by conducting twocomponent (north-south and east-west directions) acceleration time histories from Java subduction seismic sources. Due to incomplete data, all acceleration time histories used in this study were collected and modified from worldwide earthquake data bases. Based on the average displacement and PGA values it can be predicted that Sermo dam is strong enough to resist an earthquake with a maximum magnitude of 8.4 Mw and minimum epicentre distance of approximately 160 Km caused by the Java subduction source.

The new Indonesian Code for seismic resistance design for building has been issued recently. It follows the concept of Risk-Targeted Maximum Considered Earthquake (MCER). Seismic risk microzonation of Semarang is analyzed using the new concept. Seismic risk microzonation study for hazard mitigation is also performed for the whole city based on deterministic approach, considering the closes distance fault (Lasem Fault). Interpretation of local site effects is performed by carrying one-dimensional ground response analysis. Depth of bedrock is estimated based on single station feedback seismometer measurement. Geotechnical parameters are interpreted from recent and previous measurements. The result of deterministic microzonation study includes the distribution of surface peak ground acceleration (PGA) and spectral acceleration due to Lasem Fault. The obtained results are compared with the distribution of surface PGA and spectral acceleration obtained through new code.

Pengembangan peta resiko gempa berdasarkan analisa hazard gempa deterministik (DSHA) merupakan salah satu tahapan yang sangat penting untuk mitigasi kegempaan Kota Semarang. Penelitian peta resiko gempa mencakup perhitungan hazard gempa, analisa kondisi tanah lokal (SSA) dan analisa tingkat resiko kegempaan. Analisa hazard gempa diimplementasikan dengan pendekatan deterministic akibat gempa untuk sumber gempa sesar aktif disekitar Kota Semarang. Parameter geoteknik diperoleh dari hasil pengamatan atau pengujian geoteknik. Hasil dari penelitian ini mencakup pengembangan peta spektra percepatan gerakan tanah di permukaan dan faktor amplifikasi percepatan tanah yang sangat diperlukan pada pengembangan peta rawan gempa Kota Semarang.[Perception Development of Seismic Risk Map Semarang City Through Deterministic Hazard Analysis Research] Development of seismic risk map based on Deterministic Hazard Analysis (DSHA) is an important step for seismic disaster mitigation for Semarang City. The study includes estimation of seismic hazard (DSHA), site specific response analysis (SSA) and risk assessment. Seismic hazard is performed based on deterministic approach considering shallow crustal fault sources influencing Semarang City. Geotechnical parameters are interpreted from previous geotechnical measurements. The result of the hazard analysis includes the distribution of site response spectral acceleration and amplification ratios are performed corresponding to seismic risk assessment for Semarang City.

The new Indonesian National Code for seismic resistance design (SNI-03-1726-2012) issued recently utilizes seismic response spectra for the whole area of the country. Site class and site coefficient are two parameters needed for designing response spectra. Site class can be estimated using average standard penetration test (N-SPT), average shear wave velocity (Vs) and average un-drained shear strength (Su) of top 30 meter soil deposit. Site coefficients can be predicted using probabilistic seismic hazard analysis (PSHA) by implementing total probability theorem. To perform PSHA, Vs30 is a parameter needed for calculating ground motion at bedrock elevation. This paper presents the results of PSHA and site class analysis using Vs30 values estimated based on N-SPT results collected from 265 boring locations in Semarang. Seismic data in a radius of 500 km from Semarang were collected for PSHA. Site class and site coefficient maps are then developed for the whole study area.