Analysis of Complex Foundation on Historical Pagoda in Thailand Using 3d Finite Element Method

Abstract

This paper presents a three-dimensional foundation numerical model of Thailand's historical building, the Wat Khao Sukim Pagoda. The Pagoda's high reputation is due to the fact that it was constructed through donations from the public. The purpose of the research is to analysis the differential settlement and define the capable layer to transmit the load from structure. Numerical analysis will significantly contribute to the construction and mitigate the impact of any potential differential settlement. The present study is using PLAXIS 3D to model the ground surface and to analyze the settlement of the complex foundations of the Pagoda, which is loaded by varying column load. Back-analysis of the single pile load test was performed to verify the soil parameters and the results of the numerical simulations were in good agreement with settlement data reported in the field. The numerical analysis showed the settlement values in Zone 1 (shallow foundation) were in the range 0.05-0.43 mm, in Zone 2 (short pile foundation) were in the range 0.42-1.98 mm, while Zone 3 (long pile foundation) had a settlement range of 0.82-1.25 mm. These results were considered acceptable due to the modes differences in values that the differential settlement did not exceed 0.75 ins or 19 mm as recommended by ACI, 2017 and ASCE/SEI 7-02, 2013. Also, Weathered Granite layer is determined as an effective layer capable of transmitting a significant load of higher than 50%.

Investigation of Differential Settlement of Pagoda Foundation Using 3d Finite Element Method

“…In a previous study [3], the assumption was that the foundations were constructed at the same time, and the differential settlement was then established by comparing the final settlement of each area, and the structure was still considered safe based on the regulations [6,7]. For the current study, as in the actual construction, a preloading concept was adopted using 3D FEM to minimize the effect of differential settlement and to investigate the approach's advantage in reducing differential settlement.…”

“…In the preliminary stage of the methodology, critical data from prior studies was compiled, specifically addressing parameters such as soil composition, characteristics of piles, data on soil layers, and the classification of pile types [3,4].…”

“…Consequently, an accurate description of the subsurface profile was made taking into account various geotechnical studies affecting the building's foundation and surroundings. In this context, the several strata of the geotechnical model of the Pagoda and its surroundings were carefully portrayed in a 3D model based on boreholes in the building's foundation [3], as shown in Fig. 2.…”

“…Fig. 2 3D soil model of Wat Khao Sukim Pagoda [3] The phases of construction were defined to carry out a detailed assessment of any settlement. Considering these phases is important in developing the model and the associated calculations as the Pagoda's building load has substantially increased through the different periods.…”

“…The 3D finite element method (3D FEM) has been applied to examine the settlement of different types of foundations, with the PLAXIS 3D software being one available computer package to model the soil and foundations. In previous analysis [3], the design period applied 100% loading for all zones since the initial construction.…”