allochthonous masses are common structures in zagros fold-thrust belt. they are generally considered as collapse structures formed by the influence of gravity and in rock units with competency contrast. however, large allochthonous masses mapped in dowgonbadan area in dezful embayment near the mountain front fault (mff) of zagros show characteristics different from the belt common collapse stru...

Progressive collapse is a kind of failure in which whole or large part of a structure collapse when a local damage occurs and distributes to other parts. Many researchers focus on the column removal analysis and study of the structure behavior under effect of gravity loads, so these investigations are mostly carried out on the tall building. Earthquake inspections indicate structural element ca...

Allochthonous masses are common structures in Zagros fold-thrust belt. They are generally considered as collapse structures formed by the influence of gravity and in rock units with competency contrast. However, large allochthonous masses mapped in Dowgonbadan area in Dezful Embayment near the Mountain Front Fault (MFF) of Zagros show characteristics different from the belt common collapse stru...

Progressive collapse is a condition where local failure of a primary structural component leads to the collapse of neighboring members and the whole structure, consequently. In this paper, the progressive collapse potential of seismically designed steel dual systems with buckling restrained braces is investigated using the alternate path method, and their performances are compared with those of...

We study structure formation in a phenomenological model of modified gravity which interpolates between ΛCDM and phenomenological DGP-gravity. Generalisation of spherical collapse by using the Birkhoff-theorem along with the modified growth equation shows that the overdensity for spherical collapse δc in these models is significantly lowered compared to ΛCDM, leading to enhanced number densitie...

We investigate the effect of modified gravity on cluster abundance and the SunyaevZel’dovich angular power spectrum. Our modified gravity is based on a phenomenological extension of the Dvali-Gabadadze-Porrati model which includes two free parameters characterizing deviation from ΛCDM cosmology. Assuming that Birkhoff’s theorem gives a reasonable approximation, we study the spherical collapse m...

Multiring basins, large impact craters characterized by multiple concentric topographic rings, dominate the stratigraphy, tectonics, and crustal structure of the Moon. Using a hydrocode, we simulated the formation of the Orientale multiring basin, producing a subsurface structure consistent with high-resolution gravity data from the Gravity Recovery and Interior Laboratory (GRAIL) spacecraft. T...

We use one-dimensional numerical simulations to study spherical collapse in the ƒ(R) gravity models. We include the nonlinear self-coupling of the scalar field in the theory and use a relaxation scheme to follow the collapse. We find an unusual enhancement in density near the virial radius which may provide observable tests of gravity. We also use the estimated collapse time to calculate the cr...

We review here some recent developments on the issue of final fate of gravitational collapse within the framework of Einstein theory of gravity. The structure of collapsed object is discussed in terms of either a black hole or a singularity having causal connection with outside universe. Implications for cosmic censorship are discussed.