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Surface peak ground acceleration (PGAM) needs for seismic forces of basement and retaining structures design. The PGAM value can be calculated using bedrock peak ground acceleration (MCEG) and multiplied it with site coefficient FPGA. For building design purposes, the MCEG value can be calculated based on the combination of DSHA (Deterministic Seismic Hazard Analysis) and PSHA (Probabilistic Seismic Hazard Analysis). Compared to the previous 2012 website response spectrum design which is displayed the PGAM value, only MCEG value at site position can be obtained from the new 2021 response spectrum design website. This paper describes the development of PGAM distribution of Semarang using Visual Basic programming language software. The distribution of DSHA and PSHA (2500 return periods) combination analysis for developing MCEG value also describes in this paper. The analysis was performed based on the earthquake record data from 1900 to 2016. The PGAM analysis was performed at 203 soil boring investigation positions and using FPGA site coefficients of SNI 1726:2019. The minimum and maximum PGAM distribution values at the study area are in between 0.45 through 0.55 g and the maximum PGAM is distributed at the northern part of the study area.

Carbon Fiber Reinforced Polymers (CFRP) are widely used as external concrete reinforcement. The behavior of T-beams strengthened in shear and flexure using CFRP sheets and plates was studied to analyze the load carrying capacity and failure mode as compared to conventional concrete members. The bonding response of the plate-to-concrete was investigated by comparing a specimen with a plate anchored at the far ends, one without anchoring. The sheets were in situ wet lay-up, the plate was pre-impregnated and pultruded during manufacturing. The test result suggested that this integrated strengthening method notably improved the load-carrying capacity, it was also demonstrated that anchoring had a positive but insignificant effect on the moment capacity and deformation. The influence of anchoring was noteworthy from the point of view that it shifted the failure mode from debonding to CFRP plate rupture. The most important factors influencing the behavior of CFRP strengthened beams are outlined.

SNI 1726:2012 states that surface spectral accelerations SMS (0.2 second) and SM1 (1 second) can be calculated by multiplying site factors Fa (0.2 second) and Fv (1 second) with spectral accelerations SS (0.2 second) dan S1 (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 SS greater than 1g or S1 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 SMS and SM1 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 SMS and SM1 at five cities calculated using site factors proposed by Stewart and Seyhan are ±15% differences compared to SMS and SM1 calculated usingSNI 1726:2012 site factors.

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.

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 analisis 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.

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 Horizontal-to-Vertical Spectral Ratio (HVSR) is a simple method for estimating the resonance frequency of sedimentary layers. This method can also be used for estimating the site amplification factor. By using the resonance frequency and the amplification factor HVSR method can also be used for predicting the depth of the bed rock or the thickness of sediment layer (Nakamura, 1989). This paper presents results of HVSR method applied to ambient vibrations for estimating the amplification factor of sedimentary layer. A total of 16 ambient vibration measurements were performed in the City of Semarang to predict the amplification factor for the shallow sedimentary layers.

Several methods for evaluating the effect of site specific condition of soil layers against earthquakes are presently available. Site Specific Analysis (SSA) and Horizontal-to-Vertical Spectral Ratio (HVSR) are two methods commonly used for estimating the amplification factor of soil layers above bedrock. SSA can be performed using subsurface shear wave velocities and dynamic soil properties (density, shear modulus and damping). The HVSR is a simple method for estimating the site amplification factor. Based on the time and budget requirement HVSR is more efficient and effective compare to SSA method.This paper presents result of SSA and HVSR methodscomparison for estimating the amplification factor of soil layers. Two boring locations and six single station seismometer tests were perform within Tembalang District Area.

One main problem characterizes linear programming is to seek the maximum or minimum of a linearexpression when the variables of the problem are subject to restrictions in the form of certain linearequalities or inequalities. Problems of this kind are encountered when we have to exploit limitedresources in an optimal way. Project Cost Evaluation which play an important role in project are ofspecial significance in this respect. The real problem of Project Cost Evaluation analysis are tomanipulate cash flow problems of project into linear programming model or mathematical model.This method should be selected technically according the actual condition of the project. In designingand selecting the mathematical models, it is necessary to take into consideration the relationshipbetween the limited resources (money) and the optimal solution.