Flat jack test

Mike Schuller discusses the origins of the flat jack test. Edited by: Jimmy Kurzawa. This technique was initially created for testing rocky terrain, having been exported to the evaluation of the stress state and mechanical behaviour of masonry structures. This technique is considered moderately destructive and has two setup outlines: using one (simple) or two (double) flat-jacks.

The simple flat – jack test allows . U laat met het tweede out-ventiel van de flat – jack.

The testing technique is based on the release of the stress in a small area of a structure by a plane cut perpendicular to its surface. The flat jack is then loaded in the cut and the pressure is gradually increased by a hydraulic pump until the state of strain is equal to the previously existing condition before the cut. Flat Jacks : Controls concrete testing equipment.

This paper presents the of in situ flat – jack tests , i. The paper presents a non- destructive testing technique deveIo- ped by ISMES to determine the state of stress and deformability characteristics of brick masonry structures. The reIiability of the test , whi ch is based on the use of special flat – jacks , has been studied by means of cal ibration tests carried out at. Flat – jack testing is a versatile and powerful technique that provides significant information on the mechanical properties of historical constructions.

In this paper, a state of the art about flat – jack testing is presented together with some experiments carried out by the authors.

In particular, ASTM and RILEM standards are . The tests were carried out on load bearing masonry walls of an 18th century building located in the historical centre of Lisbon taking advantage of the flat-jack method. These in situ tests aimed the evaluation of the rubble stone masonry deformability properties in compression (double flat – jack test ) and the shear strength. Structural Engineering. Politecnico of Milano. Leonardo da Vinci, 32.

A long experience of application was developed by several . This method was used in several large dam sites in Portugal and some other countries. The complete test is developed in two steps: DETERMINATION OF THE STATIC LOAD (TENSILE STATUS) One flat jack is used. Two datum points are fixed across a mortar joint and the distance between the points is measured. Successively a horizontal cut is carried out with the suitable tool (drill, cutting saw ) level with the . The application of flatjack testing to the nondestructive evaluation of unreinforced , solid-unit masonry is presented. The flatjack method provides a direct measure of the state of compressive stress, deformabifity, and compressive strength.

Laboratory test have shown that the flatjack method provides an accurate. SYNOPSIS Large flat jack tests are used to assess rock mass deformability in the design stages of large projects. The paper introduces a methodology for interpretation of the tests, with which it is also possible to obtain the in situ normal and she. Sisgeo supply a complete set for flat jack tests : flat jack pressure pa tubes and valves, pump, manometers and electrical pressure transducers.

It is a minor destructive test used to assess the in situ mechanical properties of masonry under vertical loads.

It is based on the use of a hydraulic jack made of light-gauge metal welded into a flat rectangular or semicircular shape that expands under hydraulic pressure. The test requires only the removal of a portion of mortar .