Pamuda Pudjisuryadi

Adaptive Meshless Local Petrov-Galerkin Method with Variable Domain of Influence in 2D Elastostatic Problems

A meshless local Petrov-Galerkin (MLPG) method that employs polygonal subdomains constructed from several triangular patches rather than the typically used circular subdomains is presented. Moving least-squares approximation is used to construct the trial displacements and linear, Lagrange interpolation functions are used to construct the test functions. An adaptive technique to improve the accuracy of approximate solutions is developed to minimize the computational cost. Variable domain of influence (VDOI) and effective stress gradient indicator (EK) for local error assessment are the focus of this study. Several numerical examples are presented to verify the efficiency and accuracy of the proposed adaptive MLPG method. The results show that the proposed adaptive technique performs as expected that is refining the problem domain in area with high stress concentration in which higher accuracy is commonly required.The effect of loading on the chloride penetration into plain concrete (PC) and fiber reinforced concrete (FRC) was studied experimentally by using modified NT Build 492 – Nonsteady state chloride migration test that include the application of loading on the specimen during the test. Three types of polypropylene fibers with different lengths and shapes were used. The concretes were tested for chloride penetration at different stress ratios under static and cyclic loading. The results of the static loading showed that there was a slight reduction in the chloride penetration under low level of compressive stress while an increase in the chloride penetration was found at higher stress level. There are significance difference in chloride penetration behavior of the plain concrete, long fiber FRC and short fiber FRC. Chloride penetration increased even more at cyclic loading conditions showing difference behavior of FRC and PC at difference number of cycle and load level.Billet scales are by-products from steel rolling mills in Nigeria that presently constitute environmental pollution. This paper reports studies carried out using these solid wastes as a partial replacement for sand in the production of concrete. Various percentages of billet scales were used in a concrete mixture of 1: 2: 4 by weight to cast concrete specimens. The compressive and tensile strengths developed were tested after 7, 14, 21, and 28 days of curing. The result of the compressive and splitting tensile strengths tests indicated that concrete strength increased with curing age. The compressive strength of 0%, and 15% replacement of sand with billet scales as obtained at 28 days are 26.0N/mm2, 26.2N/mm2. 15% optimal replacement of sand with billet scales had similar results as the control mixture of 0%, which could be used in reinforced concrete structures. Other replacements could be useful as mass concrete for non-structural construction applications.This paper presents a site-specific seismic hazard study to determine the recommended seismic design criteria for Suramadu Bridge. The study is performed using probabilistic seismic hazard approach to determine maximum acceleration and response spectra at bedrock and followed by local site effect analysis to determine maximum acceleration and response spectra at ground surface. The probabilistic seismic hazard analysis (PSHA) is carried out using 3-dimension (3-D) seismic source models (fault source model). Two hazard levels are analysed to represent 150 and 3,300 years return period of ground motion around site location. The local site effect analysis is performed using 1-dimension (1-D) shear wave propagation theory to obtain peak ground acceleration and response spectra at ground surface. Finally, the site-specific surface response spectra with 5 percent damping are developed based on the mean plus one standard deviation concept from the result of local site effect analysis.Appropriate trust and leadership have been frequently cited as key answer to the problems of cooperation and coordination in contractor’s teamwork. The objectives of this paper are to measure trust level of construction projects team, to investigate trustworthy leadership behavior of project managers, and to model the influence of project managers’ trustworthy leadership behavior upon team trust level. Sixty-one respondents from nine on-going construction projects participated in the questionnaire survey. The analyses show that in general the levels of trust and project managers’ trustworthy leadership behavior are medium (scores of 82.71 and 102.09 respectively). Meanwhile the positive influence of project managers’ trustworthy leadership behavior upon team trust level, modeled through multiple regression analysis with one dependent variable (i.e. trust) and three independent variables (i.e. leadershipresults, leadership-integrity, and leadership-concern), is found to be significant. The model is evaluated and validated; the results reveal that the prediction of the model is satisfactory.

INTRODUCTION TO MESHLESS LOCAL PETROV-GALERKIN METHOD

In recent years, meshless methods have been developed as alternative numerical approaches in efforts to eliminate known drawbacks of the Finite Element Method (FEM). The main objective in developing meshless methods was to eliminate, or at least reduce, the difficulty of meshing and remeshing of complex structural elements. The nature of various approximation functions employed by meshless methods allows the definition of problem domains by simply adding or deleting nodes where desired. Nodal connectivity to form an element as in FEM method is not needed, only nodal coordinates and their domain of influence (DOI) are necessary to descretize the problem domain. Meshless methods may also reduce other problems associated with the FEM, such as solution degradation due to locking and severe element distortion [1].

MOVING LEAST-SQUARES APPROXIMATION TO BE USED WITH MESHLESS NUMERICAL ANALYSIS METHODS

Meshless Numerical Analysis Method adalah suatu metode analisa numerik yang berkembang dengan pesat sebagai alternatif metode elemen hingga (Finite Element Method) yang sudah cukup terkenal. Makalah ini merupakan seri pertama dari dua untuk mengenalkan salah satu shape function yang banyak digunakan untuk Meshless Numerical Analysis Method. Makalah seri kedua akan memperkenalkan salah satu Meshless Numerical Analysis Method yang dikenal sebagai Meshless Local Petrov-Galerkin Method.

STUDI TENTANG DAKTILITAS STRUKTUR PADA SISTEM SHEARWALL FRAME DENGAN BELT TRUSS

The essence of building design process and management for building sustainability in the creation and maintenance of a qualitative architectural product is investigated in this paper. The design process, concept of building sustainability and particularly the quality of the built environment are discussed. Akure, a state capital in Nigeria was used as a case study. The principles and indicators for sustainability of buildings and its implications on the quality of the environment are examined in details. Survey findings include the views of the professionals on the clients, perception on the design process as well as management of projects, and the implications on the quality of the ensuring products and the city’s environment. The data were factor analyzed using varimax rotation criterion (with Kaiser Normalization). The results revealed that five factors were effective, with one of them exhibiting the greatest variability and individual differences. The variables that loaded on this factor were really the aspects of the process and management relating to the clients. The findings also revealed the professionals’ wrong attitude towards design process as shown with a very high degree of variability in the study. The paper concludes by recommending the enactment and enforcement of relevant policies with adequate education of the people and the involvement of all the stakeholders in the management of building projects and environmental programmes for the realization of a qualitative architectural product.