ANALISIS FONDASI BORED PILE PADA GEDUNG 23 LANTAI DI TANAH LEMPUNG DAERAH CIBUBUR

Indonesia terletak pada pertemuan antara lempeng tektonik yang akibat pertemuan tersebut membentuk gugusan kepulauan di Indonesia. Konsep bangunan tahan gempa wajib dipahami dan dapat dilakukan inovasi berupa bangunan tahan gempa agar dapat meminimalisir terjadinya kerusakan struktur dan adanya korban jiwa akibat gempa bumi yang terjadi. Bangunan tahan gempa yang dimaksud adalah sebuah bangunan yang tidak mengalami kegagalan atau tidak mengalami kerntuhan pada saat gempa besar terjadi dapat memberikan waktu untuk melakukan evakuasi lebih lama. Fondasi didefinisikan sebagai bagian dari struktur bangunan yang berhubungan langsung dengan tanah dan berfungsi untuk menyalurkan beban yang diterima dari struktur atas ke lapisan tanah. Penelitian ini dilakukan pada lokasi perancangan pembangunan struktur gedung beton bertulang 23 lantai yang akan dibangun di Jl. Raya Alternatif Cibubur (Trans Yogie), Cibubur Depok (16945). Perencanaan fondasi ini menggunakan metode Meyerhoff dengan memakai data NSPT pada boring hole 2. Diameter tiang fondasi yang digunakan adalah 80 cm dengan kedalaman 20 m. Daya dukung ultimit tiang yang didapatkan adalah 906,708 ton dengan faktor keamanan 2,5 sehingga didapat daya dukung ijin tiang sebesar 362,431 ton. Penurunan fondasi tiang terjadi sebesar 0,0323 m atau setara dengan 32 mm dimana penurunan ini termasuk ke dalam batas aman penurunan yakni kurang dari 65 mm.

The Step Feed Mechanisms For Auger Machines

The paper presents the results of studies of technical solutions proposed in Kuzbass State Technical University and implemented in auger drilling equipment, characterized by the presence of a cyclic feed of a boring machine on the face and the corresponding reverse of the work by hydraulic jacks. Operation of complexes, which design feature is to provide a common plane for the axis of the boring hole and vectors of axial forces of the auger feeding mechanisms, was researched. The stress state of the cyclic step-feeding mechanism’s functional elements by mathematical and software means of the finite element analysis is considered. The threshold values of the feed forces are determined from the point of view of ensuring the safety margin of welded joints used in the cyclic step-feeding mechanism’s structure, and from the point of operational reliability of the system as a whole. The obtained data allowed making recommendations for further improvement for the subsystem of the auger’s cyclic step-feeding mechanism.

Dust Collection Validity and Effect of Hole Shape Accuracy of CFRP with Developed Hollow-Type Drill and Dust Collector

The drilling of carbon fiber-reinforced plastic (CFRP) has many important aspects, such as collecting the fine cutting chips. Serious problems relating to machining accuracy can arise when the fine cutting chips diffused into the air are deposited or mixed in the sliding surface and spindle unit of a machine tool. Moreover, the environmental aspects of fine cutting chips can seriously affect the health and safety of workers. Our group has developed a new hollow-type drilling device with a cyclone-type dust collection system, which aspirates and ejects fine cutting chips from a penetration hole in the central part of the drill shank to outside the cutting area. We produced the tools with drills both without a point angle for the counter-boring hole processing and with a point angle for general drilling. In this study the effect of the dust collection rate for cutting chip and the drilling hole shape accuracy are evaluated for the hollow-type drill with two different cutting edge shapes. The results demonstrate the possibility of suppressing the occurrence of fine cutting chips when the hollow-type drill edge is similar to the shape of general twist drill edges. The hole-finish surface properties were improved, and we obtained a higher dust collection rate.