Accuracy and precision of the CSLT measurement system: An experiment to defect diagnoses in bored piles

A new measurement system called Crosshole Sonic Logging Tomography (CSLT) provides information on the size, shape, and orientation of defects in a bored pile. The CSLT measurement system has not (yet) been accredited in Hong Kong for foundation testing. Bored piles in Hong Kong are generally wide and deep. Existing measurement accuracy studies do not consider this large type of bored piles. The objective of this research is to quantify the measurement accuracy and precision of the CSLT method for large diameter bored piles (the most common pile type for public housing projects in Hong Kong). A test pile was constructed with known defects and perform experiments with a CSLT measurement system to quantify its accuracy and precision. CSLT is found to be accurate in detecting shape, size, and location of large defects but small defects close to the tube are difficult to detect. Generally speaking, CSLT has satisfactory accuracy and precision for practical use. The use of CSLT can be considered as a feasible method in defect diagnosis of bore piles in Hong Kong.

Potential and prospects of photocatalytic disinfection: using sustainable solarenergy- driven photocatalysts

A new measurement system called Crosshole Sonic Logging Tomography (CSLT) provides information on the size, shape, and orientation of defects in a bored pile. The CSLT measurement system has not (yet) been accredited in Hong Kong for foundation testing. Bored piles in Hong Kong are generally wide and deep. Existing measurement accuracy studies do not consider this large type of bored piles. The objective of this research is to quantify the measurement accuracy and precision of the CSLT method for large diameter bored piles (the most common pile type for public housing projects in Hong Kong). A test pile was constructed with known defects and perform experiments with a CSLT measurement system to quantify its accuracy and precision. CSLT is found to be accurate in detecting shape, size, and location of large defects but small defects close to the tube are difficult to detect. Generally speaking, CSLT has satisfactory accuracy and precision for practical use. The use of CSLT can be considered as a feasible method in defect diagnosis of bore piles in Hong Kong.

Perbaikan dan Perkuatan Fondasi Tiang Bor pada Bangunan Gedung Perkuliahan dengan Penambahan Tiang Pancang Bulat

Fondasi harus dibangun di atas tanah keras agar bangunan tetap stabil dan kokoh. Memastikan kekuatan fondasi adalah upaya dini untuk mencegah sudden collapse pada bangunan di kemudian hari. Penelitian ini dilakukan untuk mengetahui kuat dukung tanah pada ujung tiang fondasi dan mengamati sejauh apa kerusakan beton tiang bor pada bangunan yang baru masih dalam tahap pembangunan fondasi. Data penelitian diperoleh dari hasil pengujian PDA (Pile Driving Analyzer) dan PIT (Pile Integrity Test) pada fondasi bangunan jenis bored pile D80. Pada gedung yang berdekatan, yang dikerjakan dengan sistem yang sama dan menggunakan spun pile D50. Data kuat dukung ultimate hasil manometer alat uji hidraulik 175 ton untuk pile D50. Dari analisis uji PDA, diperoleh nilai kuat dukung ijin rata-rata tiang bor adalah 70,25 ton (51%). Analisis ulang terhadap kombinasi beban menghasilkan tambahan spun pile di 44 titik. Pada beton bored pile yang mengalami kerusakan, dilakukan perbaikan seperti penambahan cor pada lapisan luar (concrete-jacketing) untuk menutupi lapisan tulangan yang terekspos, dan penambahan tulangan terpisah di sisi dalam beton untuk antisipasi bila tulangan luar rusak akibat korosi.The foundation must be placed on hard rock so that the building remains stable and solid. Thus, ensuring the strength of the foundation is an early effort to prevent sudden collapse of the building in the future. This research was conducted to determine the bearing strength of the soil at the ends of the foundation piles and to observe the extent of the damage to the drill pile concrete in the new building which is still in the foundation construction stage. The research data were obtained from the results of PDA (Pile Driving Analyzer) and PIT (Pile Integrity Test) testing on the foundation of the bored pile type D80 building. The adjacent building is being worked on with the same system and using a D50 spun pile. With the ultimate bearing strength data, the results of the hydraulic tool manometer = 175 tons for D50 piles. PDA test analysis obtained the average allowable bearing strength of the drill pile is 70.25 tons (51%). The re-analysis of the load combination resulted in additional spun piles at 44 points. In the damaged bored pile concrete, namely by adding cast to the outer layer (concrete-jacketing) to cover the exposed reinforcement layer, and adding separate reinforcement on the inside of the concrete to anticipate if the outer reinforcement is damaged due to corrosion.Fondasi harus dibangun di atas tanah keras agar bangunan tetap stabil dan kokoh. Memastikan kekuatan fondasi adalah upaya dini untuk mencegah sudden collapse pada bangunan di kemudian hari. Penelitian ini dilakukan untuk mengetahui kuat dukung tanah pada ujung tiang fondasi dan mengamati sejauh apa kerusakan beton tiang bor pada bangunan yang baru masih dalam tahap pembangunan fondasi. Data penelitian diperoleh dari hasil pengujian PDA (Pile Driving Analyzer) dan PIT (Pile Integrity Test) pada fondasi bangunan jenis bored pile D80. Pada gedung yang berdekatan, yang dikerjakan dengan sistem yang sama dan menggunakan spun pile D50. Data kuat dukung ultimate hasil manometer alat uji hidraulik 175 ton untuk pile D50. Dari analisis uji PDA, diperoleh nilai kuat dukung ijin rata-rata tiang bor adalah 70,25 ton (51%). Analisis ulang terhadap kombinasi beban menghasilkan tambahan spun pile di 44 titik. Pada beton bored pile yang mengalami kerusakan, dilakukan perbaikan seperti penambahan cor pada lapisan luar (concrete-jacketing) untuk menutupi lapisan tulangan yang terekspos, dan penambahan tulangan terpisah di sisi dalam beton untuk antisipasi bila tulangan luar rusak akibat korosi.

Hybrid Energy Piles as a Smart and Sustainable Foundation

The disused factories’ areas represent a considerable part of the industrial archaeology of the city of Naples. In the last decades of the previous century, many of these factories were disused also because of the ban of asbestos production by the Italian law 257/1992. Of course, this was not the only problem that concurred to create a large amount of disused industrial areas. Often the simple delocalisation of manufactories in other countries contributed to this problem. The reuse of these areas requires polluted and contaminated land reclamation. The simple removal of the shallow soil layers is a widely used reclamation procedure. Furthermore, drilling operations either for piling or for tunnelling may incur in the same type of problem taking into account that this movement can be very expensive depending on the total volume of soil to be removed and to be taken to disposal. In this study a hybrid pile type is proposed as an environmentally friendly and a cheap solution. Hybrid piles are installed by a combination of pushing and augering technique. This installation method allows avoiding the removal and the subsequent disposal of shallow contaminated soil. The mechanical behaviour of three hybrid piles equipped with strain gauges along the shaft is investigated via three loading tests. In the framework of the design of a new mall in a disused industrial area, the opportunity to provide a fully sustainable foundation solution by equipping the piles with heat exchangers pipes is also investigated. Numerical simulations of the energy hybrid pile behaviour are presented outlining further benefits of the new hybrid installation technique and comparing two different configuration of the heat exchanger pipes. Doi: 10.28991/HEF-2021-02-03-010 Full Text: PDF

New Approach in Developing Minimum Facility Platform (MFP) Through Standardization Design in Medco E&P Offshore

The purpose of this paper is to explain a new approach has to be taken by Medco E&P Indonesia in order to meet cost optimization and schedule efficiencies in the development of marginal fields which become necessary to streamline the design process for platforms and employ value engineering consideration. Development of marginal fields using minimum facilities platform rely on existing infrastructure has enabled oil and gas operators to build the minimum platform without the large capital expenditure associated with the new production facilities. This paper will show that minimum facilities platform (MFP) can be selected and developed at relatively low cost and designed to suit the specific topside surface facility and fabrication and/or installation requirements according to weight and quantity of equipment in the platform. The biggest challenges involved in the design of minimum facilities platform are the fields have 300 feet (90 m) water depth in average, environmental conditions and no experience previously to design of minimum facilities platform to cover topside requirements such as drilling, surface facilities and substructure requirements such as mono pile type, jacket types and conductor legs. Classification of the minimum facility platform design concept types and design selection guideline are therefore possible to be quickly developed within a range of structural solutions and topside design which is inherently safe as far as practicable, fit for purpose and in reliable manner. This new approach successfully brings up some minimum facilities platform to be implemented in the marginal fields to extend remaining life of the existing facilities economically and within value engineering manner.

Field Axial Loading Tests of Screw Micropiles in Sand

A screw micropile consists of a smooth shaft at the top, threaded shaft at the middle and tapered shaft at the bottom. Research is required to investigate the axial behavior and capacities of this pile type in sand. A field load test program was performed on six types of full-scale screw micropiles installed at a sandpit site using torque. Selected piles were instrumented with axial strain gauges. A geotechnical investigation, including cone penetration tests (CPT) and standard penetration tests, was undertaken. In total, 41 piles, including 8 instrumented piles, were tested. The ultimate capacities and the unit shaft resistance distributions were determined. The shaft resistance was then compared with the tip resistance of CPT. The coefficient of lateral earth pressure and combined shaft resistance factor was determined for each pile segment, and then an effective stress method based on the combined shaft resistance factor was used to estimate the capacity of test piles. A theoretical torque model was developed using CPT sleeve friction; the model was verified by comparing the estimated torque to the measured torque of test piles. In the end, empirical torque factors were developed.

DESIGN OF COMPOSITE GIRDER STRUCTURE BRIDGE OF SELUANG-1 RIVER PT LIFERE AGRO KAPUAS, KAPUAS DISTRICT

The bridge at the Seluang-1 river is located around the palm oil plantation land owned by PT Lifere Agro Kapuas, Kapuas Regency, Central Kalimantan. In this Seluang-1 river, a bridge is planned to be built to facilitate the mobilization of palm oil plantation crops and other matters as well as transportation in the PT Lifere Agro Kapuas area because before there was a bridge the transportation traffic was cut off by the river so it had to circle quite a long way. The bridge is designed as a bridge with composite girder structure type. The methodology in the design of loading uses the SNI 1725-2016 concerning on the Loading Standards for Bridges and SNI 2833-2016 concerning on the Earthquake Resilience Planning Standards for Bridges. For methodology in designing concrete structures refer to SNI 2847-2013 concerning Structural Concrete Requirements for Buildings and methodology in designing steel structures refers to SNI 1729-2015 concerning Specifications for Structural Steel Buildings. The material used for abutment uses reinforced concrete material. The methodology in calculating the bearing capacity of the foundation uses the method by Mayerhof and also the method by Kazuto Nakazawa, while the methodology in calculating the lateral bearing capacity uses the Broms method, with the efficiency of the pile using a graph by O’Neill. From the results of topographic measurements taken a bridge design with a span of 30 m with a total bridge width of 7 m. The slab design is 25 cm thick with the compressive strenght of concrete is fc’ 30 MPa (K-350). The steel girder beam used WF Profile 1350.800.100.130 and the diaphragm beam used WF Profile 250.125.6.9 with BJ55 steel quality (fy 410 MPa). Whereas in the lower structure, the abutment designed with a height of 350 cm, a width of 320 cm and a length of 850 cm, was used with compressive strenght of concrete is fc’ 30 MPa (K-350). In the foundation used Spun Pile type piles with a diameter of 60 cm with a depth of 30 m piling as much as 8 piles on one abutment. Obtained Qallow = 116,37 tons > Qload = 114,69 tons so that the foundation is declared safe. The planned budget for the construction of a bridge on the Seluang-1 river is Rp 8.990.566.000,00.-

Evaluation of non-productive time when calculating pile-type dredge performance

The paper assesses the raw material base and prospects of the dredging method to develop placer deposits and justifies the necessity to enhance its efficiency, including the reduction of non-productive time of mining equipment. Specific features of dredging that cause technological non-productive time of the dredge are described and compared to mining with continuous bucket excavators. In order to analyze and assess the impact of non-productive time on the dredge performance, it is proposed to divide all time consumed into groups, identifying time losses associated directly with working on the front bank, time spent on operations between the dredging cycles and other downtime required for technical support of the dredge operation. The main types of work are described that are part of the technological cycle in dredging and therefore define non-productive time, as well as those classified as auxiliary and organizational work. The possibility of combining non-productive time related to some auxiliary work with non-productive time due to organizational reasons is assessed. A formula is proposed for determining the front bank coefficient which is used in calculation of the dredge's technical capacity. Organizational time losses are proposed to be taken into account as the dredge utilization factors, including those per day, month and year. Specific features that cause nonproductive time in mining of formations that contain oversized boulders are highlighted. For the accepted operating conditions of the dredge and the front bank parameters, a structure of time losses was determined by type of work and their quantitative assessment was made. The results of this assessment showed the dependence of the front bank coefficient on the width and the thickness of the pay zone. The results of comparing the calculated values of the front bank coefficient with production and specialist data are provided.