Numerical Modeling of a Church Nave Wall Subjected to Differential Settlements: Soil-Structure Interaction, Time-Dependence and Sensitivity Analysis

ABSTRACT

Historic masonry structures are particularly sensitive to differential soil settlements. These settlements may be caused by deformable soil, shallow or inadequate foundation, structural additions in the building and changes in the underground water table due to the large-scale land use change in urban areas.

This paper deals with the numerical modeling of a church nave wall subjected to differential settlement caused by a combination of the above factors. The building in question, the church of Saint Jacob in Leuven, has suffered extensive damage caused by centuries-long settlement. A numerical simulation campaign is carried out in order to reproduce and interpret the cracking damage observed in the building.

The numerical analyses are based on material and soil property determination, the monitoring of settlement in the church over an extended period of time and soil-structure interaction. A sensitivity study is carried out, focused on the effect of material parameters on the response in terms of settlement magnitude and crack width and extent. Soil consolidation over time is considered through an analytical approach. The numerical results are compared with the in-situ observed damage and with an analytical damage prediction model.

KEYWORDS:

• Finite element modeling
• historic structures
• masonry
• settlement-induced damage
• soil-structure interaction

Highlights

• A masonry church nave wall subjected to differential settlements is numerically modeled, considering time-dependent material properties combined with changes in geometry and loading

• The foundation and the soil properties are directly considered

• A sensitivity analysis highlights the parameters affecting the cracking pattern and extent

• The phased analysis results in a much more accurate representation of the observed damage compared to a single-phase model

• An analytical model for the calculation of damage due to differential settlements is expanded and compared to the finite element analysis results

Notation

$E$	=	Young’s modulus
$\nu$	=	shear modulus
$\nu$	=	Poisson’s ratio
$\rho$	=	mass density
${\sigma }_t$	=	tensile stress
${\epsilon }_{cr}$	=	crack strain
${\epsilon }_u$	=	ultimate strain
$f_c$	=	compressive strength
$f_t$	=	tensile strength
$G_f$	=	tensile fracture energy
$h$	=	characteristic finite element length
$L^j$	=	footing half-length
$B^j$	=	footing half-width
$D^j$	=	footing embedment depth
$A_f^j$	=	footing area
$A_w^j$	=	footing side-wall contact area
$K_n^j$	=	footing vertical elastic stiffness
$k_n^j$	=	footing modulus of subgrade reaction
$k_n$	=	wall/colonnade modulus of subgrade reaction

Acknowledgments

The authors acknowledge the funding received by BRAIN.be, Belspo in support of the GEPATAR research project (“GEotechnical and Patrimonial Archives Toolbox for ARchitectural conservation in Belgium” BR/132/A6/Gepatar).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the BRAIN.be, Belspo [BR/132/A6/Gepatar].