Banca de DEFESA: ANA CAROLINA LIRA DE LIMA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ANA CAROLINA LIRA DE LIMA
DATE: 27/03/2024
TIME: 14:00
LOCAL: meet.google.com/jcy-txww-gpg
TITLE:

LABORATORY EQUIPMENT FOR STUDYING THE RESPONSE OF THE BACKFILL SOIL OF INTEGRAL BRIDGE ABUTMENTS SUBJECT TO CYCLIC LATERAL MOVEMENTS

KEY WORDS:

Integral bridge; bridge abutment; physical modeling, data acquisition system, earth pressure; ratcheting.

PAGES: 120
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Geotécnica
SPECIALTY: Fundações e Escavações
SUMMARY:

The backfill soil next to integral bridge abutments is subjected to cyclic loading, due to thermal variations of the structure, which may induce the increase of the lateral earth pressures in the abutment wall face and the buildup of permanent deformations (ratcheting) in the soil mass. Although a large number of integral bridges have been built in North America, Europe and in some other places so far, its accessibility still faces uncertainties about understanding the soil-structure interaction involved. However, experimental studies with reduced-scale physical models can help clarify the mechanisms that cause the detrimental effects in the backfill near the abutment in the long term. This work aims at presenting and discussing the development and validation of a laboratory equipment designed to model the response of soil subjected to cyclic lateral displacements. A steel testing box, instrumented with pressure and displacement transducers, was developed with the capacity to contain a volume of soil of 300 x 300 x 350 mm. The data generated by the transducers are collected by a low-cost data acquisition system built with open-source hardware and software. One of the walls of the testing box can apply cyclic rotational or translational displacements in the soil mass, as to simulate the behavior of the backfill soil of an integral bridge abutment when the structure is subjected to temperature fluctuations. Settlements on the soil surface and deformation fields within the soil mass were captured by a digital image correlation technique. The images were acquired from a transparent side wall of the testing box and were processed using the Ncorr algorithm via Matlab. A series of experiments were conducted to validate the testing apparatus and the data acquisition system, as well as to evaluate the general behavior of the soil upon cyclic loading. The results showed a good performance of the equipment for rotational movements around the base. The low-cost data acquisition system was also found to meet operational requirements. The findings from the physical models revealed a noticeable increase of the passive lateral earth pressure with cycling and the early appearance of ratcheting in the early cycles of imposed lateral displacements.

COMMITTEE MEMBERS:
Presidente - 2551234 - YURI DANIEL JATOBA COSTA
Interna - 1524077 - CARINA MAIA LINS COSTA
Externo à Instituição - FERNANDO LUIZ LAVOIE - USP
Externa à Instituição - SILVIA CRISTINA JUSTO FERNANDES NOBRE DE ARAUJO