Impact of pile-to-cap fixity on the design and behavior of sensitive structures

This paper presents the results of analytical studies on the connection between piles and pile caps or footings. Two nonlinear finite element analysis software packages were used to investigate the behavior of the connection itself and the impact of connection assumptions on the overall behavior of different sensitive structures such as simple spans with uneven span lengths, segmental box girders with fixed pier tables, and straddle bents with temperature loading. Results show that the behavior of the connection is affected by variables such as pile size, pile embedment length, pile cap concrete strength, interface reinforcement, and distance between the edge of the pile and the edge of the pile cap. The study also demonstrated that significant moment can develop even with shallow pile embedment lengths. The assumed level of fixity between the pile and pile cap was found to significantly influence the behavior of some of the bridges investigated in this study.

Factors Causing Delay in Pile Cap Work (Case Study: Trans Studio Mall Makassar Upgrade Project)

Pile cap as an important part used in construction engineering. Construction projects have a completion schedule, and pile caps as part of a construction project must not be delayed. The purpose of this study is to determine the factors that cause delays in Pile cap work. The analysis method to calculate the results of questionnaire distribution is simple correlation analysis. The results of this study indicate that there are seven factors causing delays Pile cap work on the Trans Studio Mall Makassar upgrade project, namely: (1) Lack of manpower, (2) Late delivery of materials, (3) Rainfall intensity factor, (4) Lack of labor expertise, (5) equipment shortage, (6) equipment damage, (7) the factor of the change of design by the owner. From the results of the calculation of the product moment correlation factor of the lack of labor with the Pearson correlation coefficient value of 0.821 has a very strong relationship.

Analytical and Experimental Study of the Piles Cap Normal and Light Weight Aerated Concrete: Literature Review

The main objective of this study is to understand the work of the pile caps made of lightweight aerated foam concrete and study the many factors affecting the ability and the capacity of the shear. The study was done by analyzing previous practical and theoretical experiences on the reinforced concrete pile caps. The previous practical results indicated that all specimens failed by shear diagonal compression or tension modes except one specimen that failed flexural-shear mode. Based on test specimens' practical results and behavior, some theoretical methods for estimating the ultimate strength of reinforced concrete pile caps have been recommended, some of which evolved into the design documents available on the subject. A theoretical and practical study of compression concluded that the shear capacity is limited by the nodal zone bearing stresses. The flexural capacity can be described by the column load that would cause the yielding of the tie (i.e., steel reinforcement). Therefore, the design of pile caps should include a check on bearing strength to be added to the traditional section force approach for pile cap design.

Damage Evolution of Concrete Piles Mixed with Admixtures in Marine Corrosion and Freeze-Thaw Environment

Marine corrosion and freeze-thaw environment will bring serious damage to marine concrete structures, leading to affect the safety and service life of structures. With the help of artificial climate and environment simulation laboratory, the variation of the compression strength and elastic modulus of concrete with the number of freeze-thaw cycles and corrosion time under the corrosion and freeze-thaw environment is studied. The results show that both of them firstly increase and then decrease with corrosion time. When the corrosion time is 270 d and the freeze-thaw time is 90 times, the strength of concrete decreases by 13% and the elastic modulus decreases by 5%. Then, based on the theory of damage mechanics, the damage evolution and constitutive model of concrete under the marine corrosion and freeze-thaw environment are established. Compared with the experimental results, it is found that the model can well describe the damage evolution characteristics of concrete under marine corrosion and freeze-thaw environment. Finally, a numerical model is established on the basis of elastic modulus and strength degradation model of concrete under marine corrosion and freeze-thaw environment. Elevated pile caps of concrete pile component are taken as an example to analyze the process of damage, and the change rules of displacement, deformation, and damage of concrete pile are obtained.

SIMULASI PERBANDINGAN TITIK JEPIT TIANG MENGGUNAKAN VIRTUAL FIXED POINT DAN LATERAL SPRING DI DERMAGA “KNP”

The jetty is the most important facility in the port because it is connected between the sea and the land. The jetty structure consists of the upper structure (beams, plates and pile caps) and the lower structure (piles). The upper structure uses reinforced concrete as the base material and the lower structure can use steel or concrete material. In designing the piles on the jetty, the depth of the fixed point is not at the seabed depth, but below the seabed. It is necessary to conduct research on the depth of the pile fixed point at KNP jetty Southeast Sulawesi. Based on the OCDI 2002 (Overseas Coastal Area Development Institute of Japan) using the virtual fixed point method (1/β), the depth of the fixed point on the KNP jetty is 24 m, meanwhile according to the lateral spring method the KNP jetty has a fixed point depth of 25,6 m. and by adding a lateral spring to the pile in the virtual fixed point method, it can also make the model more efficient with a smaller deflection of 6,43% for deflection due to earthquake in the x direction and 7,25% for deflection due to earthquake in y direction. ABSTRAKDermaga merupakan fasilitas yang paling penting pada pelabuhan karena menghubungkan antara laut dan daratan. Struktur dermaga terdiri dari struktur atas (balok, pelat dan pile cap) dan struktur bawah (tiang pancang). Struktur atas menggunakan bahan dasar beton bertulang dan struktur bawah dapat menggunakan bahan baja atau beton. Dalam mendesain tiang pancang pada dermaga, kedalaman titik jepit tidak berada pada kedalaman seabed tetapi berada dibawah seabed. Perlu dilakukan penelitian tentang kedalaman titik jepit tiang pancang. Studi kasus yang dibahas pada penelitian ini adalah dermaga yang berlokasi di Kendari, Sulawesi Tenggara. Dermaga tersebut dikenal dengan nama dermaga “KNP”. Berdasarkan OCDI (Overseas Coastal Area Development Institute of Japan) tahun 2002 dengan menggunakan metode virtual fixed point (1/β) memiliki kedalaman titik jepit pada dermaga “KNP” sebesar 24 m, sedangkan menurut metode pegas lateral pada dermaga “KNP” memiliki kedalaman titik jepit sebesar 25,6 m dan dengan menambahkan pegas lateral pada tiang pancang dalam metode virtual fixed point juga dapat membuat model lebih efisien dengan defleksi yang lebih kecil sebesar 6,43% untuk defleksi akibat gempa arah x dan 7,25% untuk defleksi akibat gempa arah y.

Structural design guidelines for Delayed Coker Unit (DCU) used in hydrocarbon industry

PurposeDelays in projects execution due to improper structural design lead to substantial losses to the owners. Little guidelines are available in practice that deals with structural design of Delayed Coker Units (DCUs). This work describes effective structural criteria for design of DCU used in hydrocarbon industry. Economical procedures are described for steel and concrete design. Design of pump houses supporting DCU is also described.Design/methodology/approachNumerical procedures are developed to model pipelines and mechanical equipment loadings. Soil restraints are simulated using horizontal and vertical springs along the pile embedded length. Concrete pile-caps are integrated with steel structure in the analysis model.FindingsThe proposed design approach is cost effective to use in practice. The paper offers economical footprint for design of DCUs that can be used for multiple projects.Practical implicationsThe paper provides useful guidelines that can be utilized by engineers for design of coker heater and coker fractionation stacks, steel modules, coke pump house, deluge building, etc.Originality/valueCurrently, there are no guidelines in practice that deal with structural design of DCU. The present work bridges this gap and describes novel strategies that can be utilized for industrial projects.