Seismic Loss Prediction for Infilled RC Buildings via Simplified Analytical Method

ABSTRACT

This work aims estimating seismic losses in residential-reinforced concrete buildings, highlighting the influence of infills and services. First, the mechanical-based “POST”-method is used to perform simplified (nonlinear static) structural analyses, in the “shear-type” building hypothesis. Then, drift-based fragility curves and repair cost analysis, specific for infills and services, are used to obtain expected damage and losses. Lastly, the whole proposed loss assessment methodology is applied to a wide building stock struck by L’Aquila (Italy) 2009-earthquake and damaged to infills. The numerical-versus-observed comparison of damage scenario and seismic losses allows a promising validation of the procedure.

KEYWORDS:

• Seismic risk
• RC buildings
• infills and services
• mechanical methodology
• damage prediction
• loss prediction
• numerical-versus-observation validation

Notation

Symbol	=	Meaning
${\nu }_{\mathrm{D}\mathrm{V}}$	=	Mean annual frequency of exceedance of a decision variable
DV	=	Decision variable
IM	=	Ground motion intensity measure
EDP	=	Engineering demand parameter
DM	=	Damage measure
Sa,e(T)	=	Spectral pseudo-acceleration
T	=	Structural period
Int. shear	=	Story shear
Int. displ	=	Interstory displacement
Δroof	=	Top displacement
Vb	=	Base shear
μR-to-R	=	Logarithmic mean of inelastic displacement demand
βR-to-R	=	Standard deviation of inelastic displacement demand
A	=	Average plan surfaces
Ns	=	Number of stories
$\widehat{S_a}\left(T\right)$	=	Median Sa,e(T) value
$\widehat{PGA}$	=	Median PGA value
L	=	Loss
a	=	Area of intervention for repairing activities
fc	=	Compressive strength of concrete
fy	=	Steel yield strength
Gw	=	Infill shear modulus
τcr	=	Infill shear strength (from diagonal compressive test)
θy	=	Yielding rotation
kelastic,infill*	=	Infill elastic stiffness
kpeak,infill*	=	Seccant to peak stiffness of infill
Fcr*	=	Infill cracking lateral load
Fmax*	=	Infill maximum lateral load
IDR	=	Interstory drift ratio
μDSi	=	Median IDR capacities
βDSi	=	Standard deviation value characterizing IDR capacities
$\bar{\mathrm{C}}$IPDSi	=	Repair costs per infill panel unit for each DSi
$C_{DSi}^{Services}$	=	Costs for services at each DSi per plan surface unit
DSmax	=	Maximum achieved DS
DEi	=	Damage extension of DSi
$\overline{\mathrm{D}\mathrm{S}}$	=	Mean damage
${\mathrm{A}}^{\mathrm{i}\mathrm{n}\mathrm{f}\mathrm{i}\mathrm{l}\mathrm{l}\mathrm{s}}$	=	Infill panel area
trc	=	Total repair cost for unit surface area
${\bar{\mathrm{n}}}_{\mathrm{i}}$	=	number of “damaged stories”
PR	=	Plan floor ratio
Lint,x	=	Total linear length of interior partitions in x-direction
Lint,y	=	Total linear length of interior partitions in y-direction
${\mathrm{C}}_{\mathrm{D}\mathrm{S}\mathrm{i}}^{\mathrm{I}\mathrm{P}}$	=	Repair costs of infills and partitions per floor surface unit

Acknowledgments

This work was developed under the support of ReLUIS-DPC 2019-2021 funded by the Italian Department of Civil Protection (DPC), PON-AIM Ricerca e Innovazione 2014-2020 – Fondo Sociale Europeo, Azione I.2, “Smart, Secure and Inclusive Communities,” and AXA Research Fund Post-Doctoral Grant “Advanced nonlinear modeling and performance assessment of masonry infills in RC buildings under seismic loads: the way forward to design or retrofitting strategies and reduction of losses.” These supports are gratefully acknowledged.

Additional information

Funding

This work was supported by the AXA Research Fund [E67G17000020007]; Dipartimento della Protezione Civile, Presidenza del Consiglio dei Ministri [E66C19000190005]; PON-AIM Ricerca e Innovazione 2014-2020 – Fondo Sociale Europeo [E66C19000230005].