Evaluation of failure and design of structural reinforcement for gabion-type retaining walls

The geological conditions of South Tangerang are generally alluvium rocks, which consist of clay, silt, sand, gravel, and boulders. This rock type has a good to moderate level of ease of work, the element of resistance to erosion is quite good, therefore the South Tangerang City area is still quite suitable for urban activities. Judging from the distribution of soil types, generally in South Tangerang there are associations of red latosol and reddish brown latosol which are generally suitable for agriculture or plantations. Based on the existing problems, a solution is needed to maintain the stability of the slopes so that subsequent landslides do not occur which can harm the surrounding community, it is necessary to construct a retaining wall to prevent landslides and increase the safety of the occupants, but still maintain the existing structure. The results of this test are used as a construction plan for the gabion type retaining wall. Tests in the laboratory carried out for planning the construction of retaining walls include soil density testing, soil density testing, direct shear strength testing, gradation inspection testing, plastic limit testing, and atterberg limit testing. The dimensions of the cantilever retaining wall construction are 4.5 meters high, the foot plate width is 0.8 meters, the foot plate height is 0.50 meters, and the top thickness of the retaining wall is 0.50 meters. The load acting on the retaining wall is 20 kN/m2. The active earth pressure load due to the earthquake based on the Mononobe-Okabe method, was 143.58 kN. Stability against shear is obtained at (Fgs) = 0.33 < SF = 1.5 and for stability against overturning (Fgl) = 0.45 < SF = 1.5, the stability to shear and stability to roll is not safe. The stability of the bearing capacity of the soil obtained a safe ultimate capacity (qs) = 252.10 kN/m2 > V = 120.0 kN/m2, so that the collapse of the bearing capacity of the soil is declared safe. Bored pile foundation is designed with a depth of 8.0 meters and a diameter of 0.50 meters, with an axial clearance capacity of 578.45 kN, and a lateral capacity of 58.02 kN

PEMETAAN POTENSI LIKUIFAKSI WILAYAH PESISIR BERDASARKAN DATA CONE PENETRATION TEST DI KELURAHAN LEMPUING, KOTA BENGKULU

Bengkulu city is one of the cities on the west coast of Sumatra island particularly vulnerable to earthquakes because it is located in an active seismic lines . This vulnerability allows the phenomenon of liquefaction when an earthquake occurs . One of the areas in Bengkulu city which through the lines is Lempuing Village . This study aims to analyze the liquefaction potential based on the data of Cone Penetration Test (CPT) using deterministic methods published by Idriss and Boulanger in 2008 . The data describes soil parameters, collected from the 6 point spread CPT test in Lempuing. Shear wave velocity data obtained from the correlation vs. the CPT data . Seismic load parameters used were obtained from the Indonesian Earthquake Hazard Map of 2010 and the seismic history of the city of Bengkulu. The magnitude of potential liquefaction happens to the value of Safety Factor (SF). The analysis at a depth of 0-2meter showed that most of the area in Lempuing with high potential of liquefaction, indicated by the value of SF is less than 1 . Furthermore , the results of the analysis are  displayed in the form of Liquefaction Potential Map . This map shows that the entire area of Lempuing be in an unsafe condition to the danger of liquefaction during an earthquake with a magnitude > 7.9 earthquake and bedrock acceleration of 0.4 g

Studi Perbandingan Daya Dukung Aksial Tiang Pancang Tunggal Persegi Berdasarkan Hasil Uji Pembebanan Statik (SLT) dan Uji PDA pada Pembangunan Apartemen Loftville City Kota Tangerang Selatan

Abstract: The deep foundation is one of the most important elements in the construction of high-rise buildings because the weight of the building will be fully borne by the foundation. This study aims to provide an overview of the prediction of the axial bearing capacity of single piles through a mathematical approach based on the results of the tests performed. The design axial bearing capacity is estimated through analysis of soil investigation results (N-SPT test results, DCPT test results, and laboratory investigation results), while the actual axial bearing capacity is obtained through interpretation of the Static Loading Test (SLT) results using the Davisson, Chin, and Mazurkiewicz, and the results of the PDA (Pile Driving Analyzer) load test were analyzed using the CAP-WAP application. The analysis was carried out on single piles with dimensions of 40x40 cm2, located in the Loftville City Apartment development project, South Tangerang City. Based on the results of the analysis that has been carried out, the planned axial bearing capacity is 131.3 tons, while the average carrying capacity based on the results of SLT interpretation on three tested piles using the Davisson, Mazurkiewicz, and Chin methods are 161.7; 205.4; and 98.8 tonnes. The results of the analysis are compared to the results of the PDA test, which shows a bearing capacity value of 290.1 tons, so the BCR values are 65.70% and 45.26% respectively. The BCR value is based on the results of the interpretation of the SLT test successively -respectively by 55.73%, 70.78%, and 34.06%. The BCR value which is not close to 100% may occur due to an error in determining the planned carrying capacity of 131 tons which is far below the actual carrying capacity value based on the PDA test results. The design carrying capacity value is then corrected to 100 tonnes and used as the 100% design load in the static load test so that the interpretation results also show BCR results that are not very accurate.Abstrak: Pondasi dalam (deep foundation) merupakan salah satu elemen yang sangat penting pada konstruksi bangunan tinggi karena beban bangunan yang besar akan dipikul sepenuhnya oleh pondasi tersebut. Penelitian ini bertujuan untuk memberikan gambaran tentang prediksi daya dukung aksial tiang pancang tunggal melalui pendekatan matematis berdasarkan hasil pengujian yang dilakukan. Daya dukung aksial rencana diperkirakan melalui analisis hasil investigasi tanah (hasil uji N-SPT, uji sondir, dan hasil penyelidikan laboratorium), sedangkan daya dukung aksial aktual diperoleh melalui interpretasi hasil uji beban statis (Static Loading Test) dengan metode Davisson, Chin, dan Mazurkiewicz, dan hasil uji beban PDA (Pile Driving Analizer) dianalisis dengan menggunakan aplikasi CAP-WAP. Analisis dilakukan pada tiang pancang tunggal dengan dimensi 40x40 cm2, berlokasi di proyek pembangunan Apartemen Loftville City, Kota Tangerang Selatan. Berdasarkan hasil analisis yang telah dilakukan, diperoleh daya dukung aksial rencana sebesar 131,3 ton, sedangkan besar daya dukung rerata berdasarkan hasil interpretasi SLT pada tiga tiang uji dengan metode Davisson, Mazurkiewicz, dan Chin berturut – turut sebesar 161,7; 205,4; dan 98,8 ton. Hasil analisis dibandingkan terhadap hasil uji PDA, yang menunjukkan nilai daya dukung sebesar 290,1 ton, sehingga nilai daya dukung rencana berdasarkan memiliki BCR berturut-turut sebesar 65,70% dan 45,26%, dan nilai BCR berdasarkan hasil interpretasi uji SLT berturut-turut sebesar 55,73%, 70,78% dan 34,06%. Nilai BCR yang tidak mendekati 100% dapat terjadi dikarenakan adanya kekeliruan dalam penentuan daya dukung rencana sebesar 131 ton yang jauh berada di bawah nilai daya dukung aktual berdasarkan hasil uji PDA. Nilai daya dukung rencana kemudian dikoreksi menjadi 100 ton dan dipergunakan sebagai beban 100% rencana pada uji beban statis, sehingga hasil interpretasi juga memperlihatkan hasil BCR yang tidak terlalu akurat

Analisis Stabilitas Dinding Penahan Tanah Saluran Irigasi Situ Bala, Desa Purwasari, Kecamatan Dramaga, Kabupaten Bogor

ABSTRAKDinding penahan tanah adalah suatu struktur yang dibangun untuk menahan tanah lateral ketika tanah mengalami perubahan dalam elevasi, dan melampaui sudut geser dalam tanah. Dinding pengaman tebingan yang terletak tepat di Situ Bala, Desa Purwasari, Kecamatan Dramaga telah mengalami kerusakan pada bagian dasar strukturnya terutama pada bagian yang terkena sistem irigasi sehingga perlu dilakukan perbaikan terhadap dinding penahan tanah eksisting. Tujuan penelitian ini adalah untuk menganalisis kondisi lereng akibat tergerus oleh aliran udara yang mengakibatkan terjadinya longsor, merencanakan dinding penahan tanah agar memiliki faktor keamanan yang cukup, dan menghitung kapasitas daya dukung tanah. Metode yang digunakan dalam penelitian ini adalah Metode Rankine .Hasil analisis menunjukkan perlindungan terhadap guling Fs= 0.86 < 1,5 (tidak aman terhadap geser Fs = 2.5119 > 1,5 (aman), dan analisis ketahanan daya dukung tanah qtoe = 12419.5895 < Qall= 4139.8631 (aman) dan qhell = 31.4263 (aman).  Kata kunci: Stabilitas, dinding penahan tanah , Metode Rankine ABSTRAKA retaining wall is a structure constructed to resist lateral soil when the soil undergoes a change in elevation and exceeds the angle of shear in the soil. The cliff safety wall which is located right at Situ Bala, Purwasari Village, Dramaga District, has suffered damage to the basic part of the structure, especially the part affected by the irrigation canal so that it is necessary to repair the existing retaining wall. The purpose of this study was to analyze the condition of the slope, where the air flow above it eroded which resulted in landslides changing the channel so that it was necessary to redesign the existing retaining wall, plan the retaining wall to be safe against shear conditions, overturning, and the carrying capacity of the soil. The method used in this study is the Rankine Method. The results of the analysis show resistance to overturning Fs= 0.86 < 1.5 (unsafe against shear Fs = 2.5119 > 1.5 (safe), and soil bearing capacity analysis qtoe = 12419.5895 < Qall= 4139.8631 (safe) and qhell = 31.4263 ( safe). Kata kunci: Stabilitas, dinding penahan tanah, Metode Rankin