scholarly journals Nacre inspired 3D printing construction for high performance structural member

2019 ◽  
Vol 275 ◽  
pp. 02005
Author(s):  
Jiangtao Yu ◽  
Junhong Ye
Keyword(s):  
Bearing Capacity ◽  
High Performance ◽  
Image Correlation ◽  
Test Results ◽  
Load Bearing Capacity ◽  
Critical Crack ◽  
Load Bearing ◽  
Hierarchical Assembly ◽  
Four Point Bending ◽  
Flexural Ductility

Inspired by the nacre’s hierarchically assembled structure, the authors tried to use ultra-high ductile cementitious composites (UHDCC) and stack approach to fabricate structure possessing high flexural ductility and load bearing capacity. A series of beams with specially design was constructed, i.e., monolithically cast beams, monolithically stacked beams and hierarchically stacked beams. Four-point bending tests were carried out to explore the effect of hierarchical assembly on load bearing capacity, flexural deformation and flexural toughness. The test results have indicated that the monolithically stacked beams outperform the monolithically cast beams in both deformability and loading bearing capacity, indicating the effectiveness of stack-based construction. Moreover, the setup of connect/separation between layers further improves the flexural ductility of the hierarchically stacked beams, as compared with the monolithically stacked beams. Digital Image Correlation (DIC) observations indicate that the nacreous-like structure of the hierarchically stacked beam helps to trigger crack deflecting and branching between layers and inside matrix, lead to limited slide between layers, thus effectively relieving concentrated strain inside matrix, postponing the emergence of the critical crack and consequently improving the flexural ductility of nacreous-like UHDCC beams.

Experimental Research on the Strengthening of RC Columns by High Performance Ferrocement Laminates

2011 ◽  
Vol 243-249 ◽  
pp. 1409-1415 ◽  
Author(s):  
Long Min Jiang ◽  
Fan Hua Tang ◽  
Man Li Ou
Keyword(s):  
Bearing Capacity ◽  
High Performance ◽  
Ultimate Load ◽  
Strengthening Effect ◽  
Test Results ◽  
Load Bearing Capacity ◽  
Rc Columns ◽  
Cracking Behavior ◽  
Load Bearing ◽  
Better Than

Eleven approximate full-size specimens including nine eccentrically compressed columns of monotonic loading and two axially compressed columns of laterally cyclic loading were tested. By a series of comparison experiment of specimens strengthened by high performance ferrocement laminates (HPFL) and no strengthened specimens, it was found that the RC columns strengthened with attached HPFL demonstrated greater degree of improving in load-bearing capacity, in which the carrying capacity increment of the strengthened eccentrically compressed columns with lesser eccentricity was greater than that of the same type of columns with bigger eccentricity under the same strengthening conditions; the strengthening effects of the specimens with lower concrete grade are better than that of those ones with higher concrete grade; the ductility and energy dissipation ability of the strengthened columns were remarkably increased. In this paper, the test results is described, the principle and regularity that this category of strengthening laminate improved the ultimate load-bearing capacity, ductility, cracking behavior and mode of failure etc. of the RC columns are analyzed. The studying results proved that this strengthening measure for RC columns is superior to make the strengthening effect notable, working behavior of strengthened column excellent, strengthening construction easy and economical.

scholarly journals Tests and Analyses of Slotted-In Steel-Plate Connections in Composite Timber Shear Wall Panels

2017 ◽  
Vol 2017 ◽  
pp. 1-20
Author(s):  
Ulf Arne Girhammar ◽  
Bo Källsner
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Design Method ◽  
Shear Walls ◽  
Test Results ◽  
Horizontal Shear ◽  
Load Bearing Capacity ◽  
Wood Panel ◽  
Load Bearing ◽  
Plate Connections

The authors present an experimental and analytical study of slotted-in connections for joining walls in the Masonite flexible building (MFB) system. These connections are used for splicing wall elements and for tying down uplifting forces and resisting horizontal shear forces in stabilizing walls. The connection plates are inserted in a perimeter slot in the PlyBoard™ panel (a composite laminated wood panel) and fixed mechanically with screw fasteners. The load-bearing capacity of the slotted-in connection is determined experimentally and derived analytically for different failure modes. The test results show ductile postpeak load-slip characteristics, indicating that a plastic design method can be applied to calculate the horizontal load-bearing capacity of this type of shear walls.

Assesment of Main Models for Predicting Debonding Load-Bearing Capacity against Intermediate Crack-Induced Debonding Failure in FRP-Strengthened RC Beams

2011 ◽  
Vol 311-313 ◽  
pp. 1941-1944
Author(s):  
Gui Bing Li ◽  
Yu Gang Guo ◽  
Xiao Yan Sun
Keyword(s):  
Bearing Capacity ◽  
Failure Mode ◽  
Failure Modes ◽  
Rc Beams ◽  
Test Results ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Accuracy Test ◽  
New Models ◽  
Debonding Load

intermediate crack-induced debondingis one of the most dominant failure modes in FRP-strengthened RC beams. Different code models and provisions have been proposed to mitigateintermediate crack-induced debondingfailure.However, these models and provisions can not mitigate this failure mode effectively. Recnetly, new models have been proposed to solve this problem. Out of all the existing models, four typical ones are investigated in the current study. A comprehensivecomparison among these models is carried out in order to evaluate their performance and accuracy. Test results offlexural specimens with intermediate crack-induced debonding failurecollected from the existing literature are used in the current comparison. The effectivenessand accuracy of each model have been evaluated based on these experimental results. It is shown that the current modals are all conservative and inadequite to effectively mitigate intermediate crack-induced debonding in flexurally strengthened members.

Stabilization of Weak Clay with Strong Sand and Geogrid at Sand-Clay Interface

1998 ◽  
Vol 1611 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Braja M. Das ◽  
Kim H. Khing ◽  
Eun C. Shin
Keyword(s):  
Bearing Capacity ◽  
Model Test ◽  
Soil Layer ◽  
Granular Soil ◽  
Laboratory Model ◽  
Test Results ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Base Course ◽  
Granular Base

The load-bearing capacity of a weak clay subgrade can be increased by placing a strong granular base course of limited thickness on top of the clay layer. The load-bearing capacity can be increased further, or the thickness of the granular base course can be reduced, by separating both layers by a geogrid. Laboratory model test results for the ultimate bearing capacity of a rigid strip loading on the surface of a granular soil underlain by a soft clay with a layer of geogrid at the interface of the two soils are presented. The optimum thickness of the granular soil layer and the critical width of the geogrid layer required to derive the maximum benefit from the reinforcement were determined. Model test results on the permanent settlement of the rigid strip load caused by cyclic loading of low frequency are presented.

FITNET FFS Methodologies for the Assessment of Low Constraint Conditions: Overview, Contents and New Contributions

2008 ◽  
Author(s):  
Sergio Cicero ◽  
Federico Gutie´rrez-Solana ◽  
Mustafa Kocak
Keyword(s):  
Fracture Mechanics ◽  
Bearing Capacity ◽  
Structural Integrity ◽  
Assessment Procedure ◽  
Notch Effect ◽  
Load Bearing Capacity ◽  
Critical Crack ◽  
Load Bearing ◽  
Low Constraint ◽  
First Time

In the last years constraint has represented one of the major issues on fracture mechanics and structural integrity research. The need of more adjusted less conservative (and still safe) assessments requires, in many cases, the consideration of the constraint conditions in the crack tip in order to make better predictions of the load bearing capacity or the critical crack dimensions. The newly developed FITNET FFS Procedure gathers a comprehensive set of methodologies for the assessment of low constraint conditions, from those ones that have their origin on the crack shallowness and/or the type of loading (something that is also treated in other procedures), to those related to the notch effect (included for first time in an assessment procedure). Moreover, one of the biggest difficulties that has been traditionally found when performing constraint assessments, has been the obtainment of the different material and constraint parameters that have to be implemented in the calculations. FITNET FFS has dedicated special efforts in providing values of these parameters for a wide variety of materials and geometries, so that the application of its constraint assessment methodologies is noticeably simplified if compared to other procedures. This paper presents these FITNET FFS constraint methodologies and the advances achieved by the procedure in the constraint field.

Experimental Study on Load Bearing Capacity of Prefabricated Partially Encased Composite Beams

2021 ◽  
pp. 2150104
Author(s):  
Kai Wu ◽  
Shiqi Lin ◽  
Xiaoyi Liu ◽  
Fanshen Mao ◽  
Chengwei Tan
Keyword(s):  
Bearing Capacity ◽  
Superposition Principle ◽  
Great Influence ◽  
Reduction Rate ◽  
Test Results ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Shear Span ◽  
Bending Capacity ◽  
Negative Effect

To study the load bearing capacity of prefabricated partially encased composite (PEC) beams, 12 specimens were tested under cyclic loadings. According to the test results, when shear span ratio increases, the failure mode of the specimen changes from shear to bending, while the load bearing capacity of specimens decreases. Some specimens showed asymmetric damage of concrete on both sides of steel web, causing specimens’ bearing capacity to be controlled by bending and shearing as well as by torsion. The use of threaded rods has little effect on the ultimate load of prefabricated PEC beams, but has a great influence on the reduction rate of the load with the increase in shear span ratio. Using the superposition principle, a formula for calculating the shearing capacity of prefabricated PEC beams was proposed. Based on the plane section hypothesis, a method for predicting the bending capacity was also proposed. Two reduction factors were proposed to account for the negative effect of asymmetric damage on the bearing capacity and the weakened bending capacity of specimens without threaded rods. The calculated results match well with the experimental ones. Therefore, they can be used to predict the bending and shearing capacity of prefabricated PEC beams, while providing a reference for engineering design.

Numerical Analysis of Masonry Enhanced by Fiber Reinforced Lime-Based Render

2014 ◽  
Vol 624 ◽  
pp. 246-253
Author(s):  
Michal Přinosil ◽  
Petr Kabele
Keyword(s):  
Numerical Simulations ◽  
Bearing Capacity ◽  
High Performance ◽  
Masonry Wall ◽  
Deformation Capacity ◽  
Fiber Reinforced ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Out Of Plane ◽  
Brittle Fiber

Out of plane load bearing capacity of a masonry structure enhanced by surface render made of high performance lime-based mortar is investigated by numerical simulations using the finite element method (FEM). The response of the wall is simulated firstly without render (as a reference) then with surface render consisting of conventional lime mortar with increased tensile strength (by addition of the metakaolin) without fibers and finally with the proposed lime-metakaolin mortar reinforced with PVA fibers. The thickness of the surface render is considered in two configurations (20 mm and 40 mm). Material parameters of masonry units (bricks), joints (mortar between bricks) and conventional plain render are chosen with regard to investigations of historic structures (reported in the literature), material characteristics of fiber reinforced render are evaluated based on experiments or numerical simulations of these experiments. Using these parameters and characteristics, the numerical simulations of masonry wall subjected to out of plane bending are performed. The results allow us to identify influence of the thickness and the material of render on load-bearing and deformation capacity, failure mode and amount and width of cracks. The results show that the conventional plain mortar improves load-bearing capacity and deformation capacity proportionately to the thickness of render, but the response remains brittle. Fiber reinforced mortar significantly increases the deformation capacity and load-bearing capacity and the amount of absorbed energy is significantly improved.

Evaluation of Main Code Models for Predicting Flexural Load-Bearing Capacity against Intermediate Crack-Induced Debonding in FRP-Strengthened RC Beams

2011 ◽  
Vol 71-78 ◽  
pp. 1465-1468
Author(s):  
Gui Bing Li ◽  
Yu Gang Guo ◽  
Xiao Yan Sun
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Experimental Results ◽  
Rc Beams ◽  
Test Results ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Accuracy Test ◽  
Comprehensive Comparison ◽  
Code Provisions

Intermediate crack-induced debonding is one of the most dominant failure modes in FRP-strengthened RC beams. Different code models and provisions have been proposed to predict intermediate crack-induced debonding failure. Out of all the existing code provisions and models, four typical ones are investigated in the current study. A comprehensive comparison among these code provisions and models is carried out in order to evaluate their performance and accuracy. Test results of flexural specimens with intermediate crack-induced debonding failure collected from the existing literature are used in the current comparison. The effectiveness and accuracy of each model have been evaluated based on these experimental results. It is shown that the current recommendations are inadequite to effectively mitigate intermediate crack-induced debonding in flexurally strengthened members.

Time-Dependent Load Bearing Capacity of Corroded R.C. Columns in Atmosphere Environment

2011 ◽  
Vol 50-51 ◽  
pp. 859-863
Author(s):  
Qiang Li ◽  
Nan Guo Jin ◽  
Xian Yu Jin
Keyword(s):  
Bearing Capacity ◽  
Time Dependent ◽  
Test Results ◽  
Equilibrium Equations ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Bond Behavior ◽  
Capacity Model ◽  
Model Predictions ◽  
Atmosphere Environment

As a supporting member of concrete structures, the reliability of the columns is of critical importance. To have models targeted to estimating the residual load-bearing capacity of corroded reinforced concrete (R.C.) columns so that inspection procedures and maintenance interventions can be well conducted, a time-dependent capacity model for corroded R.C. column is presented. The model was based on equilibrium equations on which load-bearing capacity of R.C. column at given time (year) can be predicted considering the overall deteriorations of rebar, concrete section, mechanical properties and bond behavior between corroded reinforcement and concrete. The model was verified by published literature test results of corroded R.C. columns served in atmosphere environment for years. The comparison of the model predictions with the test results shows the validity of the model. In the end, considerations for use of the model were suggested.

Simplified Model to Predict Load-Bearing Capacity of Concrete-Filled Steel Tubular Laced Column

2013 ◽  
Vol 405-408 ◽  
pp. 1041-1045 ◽  
Author(s):  
Lian Qiong Zheng ◽  
Shu Li Guo ◽  
Ji Zhong Zhou
Keyword(s):  
Bearing Capacity ◽  
Slenderness Ratio ◽  
Steel Tube ◽  
Simplified Model ◽  
Test Results ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Concrete Filled Steel Tube ◽  
Simplified Method ◽  
Equivalent Slenderness Ratio

A simplified method using an equivalent slenderness ratio was suggested to calculate load-bearing capacity of concrete-filled steel tubular laced column in this paper. The significant differences between compressive and tensile strengths of concrete-filled steel tube were considered. The comparisons between the predicted Nuc and the tested Nue showed that the predicted method gives generally good predictions of the test results.

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