Browsing by Author "Popov, Egor P."

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Open Access
Analytical model for concrete anchorages of reinforcing bars under generalized excitations
(1982) Ciampi, Vincenzo; Eligehausen, Rolf; Bertero, Vitelmo V.; Popov, Egor P.
This report presents an analytical model for predicting the behavior of single deformed reinforcing bars embedded in confirmed concrete and subjected to generalized excitations in the range of low cycle fatigue. The model is based on a general local bond stress-slip relationship, derived from the results of an extensive study performed at Berkeley, and on either a bilinear or a simple but sufficiently accurate nonlinear stress-strain relationship for the reinforcing steel bar. An efficient numerical scheme for the integration of the governing differential equation of bond along the embedment length of the bar is presented.
Open Access
Analytical model for deformed bar bond under generalized excitations
(1981) Ciampi, Vincenzo; Eligehausen, Rolf; Bertero, Vitelmo V.; Popov, Egor P.
Ein mathematisches Modell zur Berechnung des Verhaltens eines Rippenstabes, verankert in eng verbügeltem Beton und beansprucht durch beliebige zyklische Belastungen hoher Intensität wird erläutert. Es umfasst die Formulierung eines vereinfachten Modells für die Beziehung zwischen örtlicher Verbundspannung und örtlichem Schlupf, das aus umfangreichen, in Berkeley durchgeführten Versuchen abgeleitet wurde; die Benutzung eines einfachen, jedoch ausreichend genauen Modells für das Spannungs-Dehnungs Gesetz des Bewehrungsstahles und die numerische Lösung der Differentialgleichung des Verbundes. Ein Beispiel ist dargestellt und erläutert.
Open Access
Behavior of deformed bars anchored at interior joints under seismic excitations
(1983) Eligehausen, Rolf; Popov, Egor P.; Bertero, Vitelmo V.
A mathematical model of a deformed bar anchored at interior joints of ductile moment resisting reinforced concrete frames subjected to severe earthquakes is presented. It includes the formulation of an accurate model for the local bond stress-slip relationship, use of a simple model for the stress-strain relationship of the reinforcing steel and the numerical solution of the differential equation of bond. The analytically predicted response of anchored beam bars compares well with tbe results of a series of tests for monotonic and cyclic loading. The influence of major parameters of the behavior of anchored bars is shown by an extensive numerical study. The results of this investigation are used to offer practical recommendations for the anchorage of beam bars at interior joints.
Open Access
Hysteretic behavior of deformed reinforcing bars under seismic excitations
(1982) Ciampi, Vincenzo; Eligehausen, Rolf; Bertero, Vitelmo V.; Popov, Egor P.
A mathematical model of a deformed bar an anchored in a concrete block, recently developed by the authors, has been generalized to cover the bond conditions found in exterior and interior joints of reinforced concrete frames subjected to severe earthquake loadings. The analytically predicted response compares well with the results of a series of tests conducted in Berkeley for monotonic and cyclic loadings. An extensive numerical investigation has been carried out to show the influence on the anchored bar behavior of different parameters such as: 1) Severity of hysteretic requirements, 2) Characteristics of steel (namely yield stress and strain hardening), 3) anchorage length. The results of this investigation are used to offer some practical recommendations and conclusions.
Open Access
Hysteretic behavior of reinforcing deformed hooked bars in R/C joints
(1982) Eligehausen, Rolf; Bertero, Vitelmo V.; Popov, Egor P.
The force-slip relationships of deformed hooked bars embedded in well confined concrete and subjected to monotonic and cyclic loadings were experimentally studied. The results were used to deduce an analytical model for the hook behavior under generalized excitations. The model is similar to the one for the local bond stress-slip relationship of deformed bars, but with some modifications to account for the different behavior of hooks. The main results of this study are reported.
Open Access
Local bond stress-slip relationships of deformed bars under generalized excitations
(1982) Eligehausen, Rolf; Popov, Egor P.; Bertero, Vitelmo V.
The local bond stress-slip relationships of deformed bars embedded in confined concrete under monotonic and cyclic loading for various bond conditions were investigated in an extensive experimental study. The results were used to deduce an analytical model of the bond behavior under random excitations. By evaluating experimental results of long anchorages, the model was extended to cover the bond conditions found in joints of R/C frames under severe seismic excitations. The model was successfully used to predict the behavior of deformed bars anchored at interior joints and subjected to various loading histories.
Open Access
Local bond stress-slip relationships of deformed bars under generalized excitations : experimental results and analytical model
(1983) Eligehausen, Rolf; Popov, Egor P.; Bertero, Vitelmo V.
This report covers integrated experimental and analytical investigations that permit predicting analytically the local bond stress-slip relationship of deformed reinforcing bars subjected to generalized excitations, such as may occur during the response of reinforced concrete (RIC) structures to severe earthquake ground motions.