Design and built of a bottom slab of 57,000 m2 in two basement

for a shopping center, founded under lacustrine soft clay deposits

of south zone of the Mexico city

5-Dec-19

Gabriel Lira Alvarez, Guillermo Clavellina Miller

1

Project location

The project site is located in the south zone of the Mexico city,

in the Acoxpa Ave. and Miramontes St. intersection.

25-Dec-19INTRODUCTION

Aereal view of the projet site previous to the kick-off

Ubicación del Proyecto

Estadio Azteca

INTRODUCTION

Arquitechtural project consider three stories above ground

surface for comercial use and two basements for parking lots and

water reservior.

Basement 1, in the whole area of the project site to 4.90m depth

and basement 2 in the center zone to 9.00m depth.

Total area of the site is near to 57,000 m2, with a trapecial form.

35-Dec-19

Characteristics of the Project

45-Dec-19GEOTECHNICAL CONDITIONS

Geotechnical zone III (color green area), lacustrine deposits, near to

the transition zone (color brown).

Seismic zone IIIa.

Geotechnical and seismic features

55-Dec-19

U1 superficial crust

U3, Sand clayed

U4 Soft clay with sand lenses

U2 Soft clay to medium clay

Water level to 2.5m depth

GEOTECHNICAL CONDITIONS

Geotechnical soil properties

65-Dec-19SCOPE “DESIGN AND BUILT”

• Cantilever diaphragm wall, thickness 50 cm,

perimeter 1100 m, 14.0 m depth

• Dewatering of the water level until 12.0 m depth

using aprox. 250 wells.

• Almost 1000 Starsol® piles, f= 600 and 800 mm, 14.0 m depth

• Excavation whole site

• Bottom slabs, Basement 1 slab 40cm thicknes with beams 1.4m height,

Basement 2 slab 50cm thickness and beams 2.0m height

75-Dec-19

Long-term condition envelopes, wáter level 2.5m depth

Uxmax= 9.7mm Mmax= 6.7t-m/m Vmax= 6.0t/m Uxmax= 19.0mm Mmax= 10.7t-m/m Vmax= 6.9t/m

Extraordinary condition envelope, wáter level -1.5m depth

SUPPORT SYSTEM

Interaction analysis for design of diaphragm wall, PARIS 2016

85-Dec-19

Axi-symetric model for strain modulus definition

Starsol® pile f=62cm

BOTTOM SLAB

Bearing capacity review and strain modulus definition

for Starsol® piles

Starsol® pile f=82cm

BOTTOM SLABS 95-Dec-19

3D Settle model for definition of theoretical displacements, maximun dewatering displacement, Uymáx =11.6 cm

Review of dewatering process for differents stages construction

BOTTOM SLABS 105-Dec-19

Propuesta de abatimiento del nivel freático

Plaxis 2D model for definition of theoretical displacements, maximun dewatering displacement, Uymáx =17.5 cm

With Plaxis 2D models, strain modulus for bottom slabs and diaphragm wall were defined

Review of dewatering process with FEM 2D anlysis

115-Dec-19

Shell elements for solid slabs were used

BOTTOM SLABS

Structural analysis with SAP2000 V18

Frame elements for beams were used

BOTTOM SLABS 125-Dec-19

Moment M11 in solid slab

Structural analyses results

Shear stress S11 in solid slab

BOTTOM SLABS 135-Dec-19

Moment force on beams (frame elements)

Structural analyses results

Deformation on bottom slab

145-Dec-19CONSTRUCTION STAGES

Diaphragm wall construction and drilling wells processs

155-Dec-19CONSTRUCTION STAGES

Temporary diaphragm wall reinforcement

Water reservior zone, for construction process Wall reinforcement, for sensitive buildings

165-Dec-19CONSTRUCTION STAGES

Bottom slab construction and pre-cast structure installation

175-Dec-19CONSTRUCTION STAGES

Bottom slabs with 95% advance

185-Dec-19CONSTRUCTION STAGES

Pre-opening views

of the shopping center

195-Dec-19CONCLUSIONS

• Develoment of an interaction analyses considering strain modulus of whole structuralelements involved in the stucture and the constructive secuence lead us to an eficientdesign of the bottom slab.

• Document show us the hypothesis and type of analysis that could be developed duringdesing process of a project with conditions or with special caracteristics.

• FEM analysis must shows more realistic behavior of the diaphragm wall versus strain-modulus analysis (PARIS software) in soft clay deposits.

• Diaphragm walls in cantilever during design phase must consider temporary flood conditionduring construction stage.