Now showing 1 - 3 of 3
  • Publication
    Theoretical solutions for strength-scaled unreinforced masonry for scaled soil-structure experimentation
    Reduced-scale masonry testing offers advantages of lower costs and shorter schedules compared to full-scale testing, but achieving results reflective of full-scale behavior requires development and fulfilment of appropriate scaling relationships. In many model-scale experiments, geometric scaling occurs but kinematic and/or dynamic similitude is not fully satisfied. This paper describes the theoretical basis and evolution of the equations necessary to achieve kinematic similitude for soil-structure testing at one-gravity for unreinforced masonry. Critical considerations relate to preventing the soil from being overloaded. By adopting a standard linear relationship of increased soil stiffness with depth, the controlling principle becomes the application of restricted, scaled loads throughout the entirety of the structure-soil system. As such, material strength and stiffness must be scaled accordingly to respond appropriately under the reduced stress. An example is provided for an adjacent excavation experiment with related empirical verification and computational quantification.
      1413Scopus© Citations 4
  • Publication
    Manufacturing, assembly, and testing of scaled, historic masonry for one-gravity, pseudo-static, soil-structure experiments
    In many model-scale experiments, geometric scaling is upheld but kinematic and/or dynamic similitude is not because of the difficulty in manufacturing and assembling small models. This paper describes scaling, manufacturing, assembly, and testing of 1/10th scaled historic masonry materials for one-gravity, pseudo-static, soil-structure testing. Prototype selection, manufacturing limitations, constructibility constraints, and testing decisions are presented, alongside details related to model construction. Compressive, tensile, and shear capacities of one-tenth scale prototype values, as well as failure mechanisms, were achieved by adopting traditional brick extrusion and firing methods, in conjunction with modifying mortar products developed for historic restoration. When scaled-masonry structures were subjected to adjacent excavation, damage levels and patterns and levels were consistent with full-scale, field observations.
      1246Scopus© Citations 25
  • Publication
    Predicting reinforced concrete frame response to excavation induced settlement
    (American Society of Civil Engineering (ASCE), 2009-11) ; ; ;
    In many tunneling and excavation projects, free-field vertical ground movements have been used to predict subsidence and empirical limits have been employed to evaluate risk. Validity of such approaches given the reality of two-dimensional ground movements and the influence of adjacent applied loads has been largely unknown. This paper employed analytical and large-scale experimental efforts to quantify these issues, in the case of a reinforced concrete frame structure adjacent to an excavation. Nearly half of all soil and building movements occurred prior to installation of the first tie-back, even when conservative practices were applied. Free-field data generated a trough half the size of that recorded near the building frames. Empirically based relative gradient limits generally matched the extent and distribution of the damage. Application of various structural limits also generally reflected global experimental response but did not fully identify local damage distribution. Fully free-field data or failure to include accurate two-dimensional soil displacements under-predicted building response by as much as 50% for low-rise concrete frames without grade beams.
      2388Scopus© Citations 29