Clay shale has unstable properties even though it is on a slope having a gentle slope. This raises many geotechnical problems. This study aims to determine the effect of clay shale drying on compressive strength and durability reduction by using samples taken from Kandangan Village, Polisiri Village, Bawen Sub District, Semarang Regency and Central Java. The drying process simulates when the open cut excavation process is exposed to sunlight, such as road excavations and bored pile excavations. The method used is testing the physical property, property of rocks and mechanical property with drying at intervals of 0 minute, 30minutes, 60minutes, and 90minutes. Initial condition of sample had 23 percent -31 percent of vulnerable water content. The influence of drying can reduce the value of water content; clay shale is really easy in creating the weathering; and all samples of shale clay have very low durability properties. Of all the UCS test samples, it can be said that the longer the drying, the greater the percentage of qu value loss. For testing Modulus Elasticity can be said that the longer the drying, the greater the percentage of loss of E50 value and Etan value. The relationship between UCS and Modulus Elasticity (E50 and Etan) values with the duration of the drying is the longer the drying the greater the lost value of UCS and Modulus Elasticity.

An expansive clay soil material that is composed of various minerals include kaolinite

The use of sand-key reclamation works in soft and very soft soils to increase the stability of the bund construction. Reclamation using the hydraulic fill method requires a stable embankment structure to withstand the potential for landslides from landfills, and in sea areas with very soft subgrade soils, with small undrained cohesion values causes the bund to be unstable and do not exceed the critical limit. The purpose of this study is to evaluate the improvement of soft soil in bund construction so that it is stable using GeoStudio. The Bund stability analysis results show that the value of the sand-key depth depends on the variation in the depth of the seabed. At a seabed depth of -6 m, there is a sand-key depth of 7 m, -5 m the sand-key depth of 10 m, -4 m thesand-key depth of 10 m, -3 m the sand-key depth is 5 m. The final safety number of 1.404,1.438,1,675, and 1.354 respectively.

For analysis purpose, the model system of structure is created as open frame structure rather than massive structure. However, the brick wall will affect to the behavior of the dynamic response when the earthquake induces the structure. The results of structural analysis by time history method using El-Centro earthquake, it reveales a significant difference of base shear between two types of structural model: (i) brick wall structure and (ii) non-brick wall structure. The base shear exists on the brick wall structure 20 percent greater than non-brick wall structure. Therefore, a structure without brick wall will be more irressistant due to the earthquake. The structural analysis using static equivalent method as point out in Standard of Earthquake Resistant for Building and Non Building (SNI 03-1726-2012) revealed that earthquake distribution loads relatively equal for brick wall structure and non-brick wall structure. The difference of earthquake load approximately 10 percent among two type of structure. Thus, it could be concluded that static equivalent method is more reliable to estimate the earthquake load of the structure rather than other method. This research suggests that in the structural design practicality, the effect of brick wall should be considered as a part of the structural analysis model.Untuk keperluan analisis, sistem struktur biasanya dimodelkan sebagai struktur rangka terbuka, dimana hanya elemen-elemen struktur yang terbuat dari material beton saja yang disusun didalam pemodelan struktur. Adanya pasangan dinding bata pada sistem struktur akan mempengaruhi perilaku dari respon dinamik struktur pada saat terjadi gempa. Dari hasil analisis struktur dengan Metode Riwayat Waktu (Time History Analysis) menggunakan gempa El-Centro, didapatkan perbedaan nilai base shear yang cukup signifikan antara struktur dengan dinding bata yang dipasang monolit dengan struktur tanpa dinding bata. Base shear yang terjadi pada struktur dengan dinding bata lebih besar 20% dibandingkan dengan beban base shear yang terjadi pada struktur tanpa dinding bata. Jika hal ini tidak diperhatikan pada saat perencanaan struktur, maka struktur akan lebih mudah rusak jika terjadi gempa. Dari hasil analisis struktur dengan Metode Statik Ekivalen sesuai yang tercantum di dalam Tata Cara Perencanaan Ketahanan Gempa Untuk Struktur Gedung dan Non Gedung (SNI 03-1726-2012), didapatkan nilai distribusi beban gempa pada struktur gedung yang relative sama besar untuk bangunan dengan dinding bata dan tanpa dinding bata. Perbedaan besarnya distribusi gaya gempa untuk bangunan dengan dan tanpa dinding bata, kurang dari 10%. Dengan demikian dapat disimpulkan bahwa Metode Statik Ekivalen ini cukup aman digunakan untuk memperkirakan beban gempa yang bekerja pada struktur.

Tinggi rendahnya tingkat kembang dan susut tanah lempung ekspansif ditentukan oleh kandungan montmorillonite yang sering menimbulkan masalah pada bangunan. Tujuan dari penelitian ini adalah menganalisa komposisi campuran soda api yang terbaik untuk memperbaiki sifat ekspansif tanah lempung. Penelitian ini menggunakan larutan soda api (NaOH) sebagai stabilisator dengan melalui  proses pemadatan Modified Proctor. Hasil terbaik diperoleh pada 25 x tumbukan, nilai dari indeks properties menunjukkan peningkatan, Uji UCS  menunjukkan penurunan, Uji CBR dengan perendaman 7 hari dengan campuran soda api 10% menunjukkan hasil yang terbaik, sedangkan nilai Tekanan Mengembang dan Potential Mengembang  mengalami penurunan yang signifikan.

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.

Residual soil is found in most areas with mountainous, hilly, and undulating topography. This soil is marked by red or brown color. This study aims to determine the physical and mechanical properties of soil in the original soil and residual soil conditions using the slurry method. Research objects were taken from residual red soil of The East Ungaran District, Bergas District, and Bawen District. Analysis of the physical and mechanical properties test shows that the soil sample is a type of clay with kaolinite constituent minerals and moderate swelling ability, and direct shear testing from locations L1, L2, and L3 obtained residual peak shear angles using the slurry method of 29,249 °; 31,341 °; 31,964 ° and constant residual shear angle value of 8,082 °; 8,138 °; 7,294 °, the value of the original soil shear angle has a value of 32.82 °; 31.44 °; 31.98. The higher the value of the plasticity index, the higher the value of the free swell. The relationship between the plasticity index and the value of the residual peak shear angle shows that the results of the peak shear angle and the plasticity index are still within the scope of standard deviation. The value of the constant residual shear angle with the slurry method is much smaller than the test result graph.

No abstract