An experimental research was conducted to determine the corrosion and bearing capacity of a reinforced concrete（RC） slab at different ages in a marine environment.Results show that the development of corrosion-induc...An experimental research was conducted to determine the corrosion and bearing capacity of a reinforced concrete（RC） slab at different ages in a marine environment.Results show that the development of corrosion-induced cracks on a slab in a marine environment can be divided into three stages according to crack morphology at the bottom of the slab.In the first stage,cracks appear.In the second stage,cracks develop from the edges to the middle of the slab.In the third stage,longitudinal and transverse corrosion-induced cracks coexist.The corrosion ratio of reinforcements nonlinearly increases with the age,and the relationship between the corrosion ratio of the reinforcements and the corrosion-induced crack width of the concrete is established.The flexural capacity of the corroded RC slab nonlinearly decreases with the age,and the model for the bearing capacity factor of the corroded RC slab is established.The mid-span deflection of the corroded RC slab that corresponds to the yield of the reinforcements linearly increases with the increase in corrosion ratio.Finally,the mechanisms of corrosion morphology and the degradation of the mechanical properties of an RC slab in a marine environment are discussed on the basis of the basic theories of steel corrosion in concrete and concrete structure design.展开更多
The Niger Delta has experienced tons of crude oil spill within their environment over the years and its impact on the environment is quite lethal. The soil is a major recipient of this spilled crude. When contaminated...The Niger Delta has experienced tons of crude oil spill within their environment over the years and its impact on the environment is quite lethal. The soil is a major recipient of this spilled crude. When contaminated with crude oil, the load bearing capacity is consequently affected. This study aimed at providing a statistical evidence to prove that the impact of crude oil contamination on the soil＇s bearing capacity is significant. Four samples of uncontaminated soil of Kwale were collected and analyzed for their load bearing properties： cohesion （c）, angle of internal friction （θ°） and bulk density （γ）. These soil samples were polluted with crude oil in levels of 5%, 10%, 15% and 20% and compared with intact soil. A consistent reduction was observed in the bearing capacity as the crude oil level increased. Using the SPSS （statistically package for social sciences）, the significance was tested at the various contamination levels at a 5% confidence level and the result showed significance at 15% and 20% levels with calculated P-values of 0.038 and 0.035 respectively for both the square and strip foundation footings.展开更多
The paper analyses the space time characteristics, primary causes and disastrous effects of the drying up of the Yellow River, and proposes the concept of "water resource bearing capacity (WRBC)", which refe...The paper analyses the space time characteristics, primary causes and disastrous effects of the drying up of the Yellow River, and proposes the concept of "water resource bearing capacity (WRBC)", which refers to the maximum bearing capacity of a river in meeting human demands for water on the precondition of sound recycling of the ecosystem. The concept encourages cautious human actions to save and conserve water resources.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.50079002)
文摘An experimental research was conducted to determine the corrosion and bearing capacity of a reinforced concrete（RC） slab at different ages in a marine environment.Results show that the development of corrosion-induced cracks on a slab in a marine environment can be divided into three stages according to crack morphology at the bottom of the slab.In the first stage,cracks appear.In the second stage,cracks develop from the edges to the middle of the slab.In the third stage,longitudinal and transverse corrosion-induced cracks coexist.The corrosion ratio of reinforcements nonlinearly increases with the age,and the relationship between the corrosion ratio of the reinforcements and the corrosion-induced crack width of the concrete is established.The flexural capacity of the corroded RC slab nonlinearly decreases with the age,and the model for the bearing capacity factor of the corroded RC slab is established.The mid-span deflection of the corroded RC slab that corresponds to the yield of the reinforcements linearly increases with the increase in corrosion ratio.Finally,the mechanisms of corrosion morphology and the degradation of the mechanical properties of an RC slab in a marine environment are discussed on the basis of the basic theories of steel corrosion in concrete and concrete structure design.
文摘The Niger Delta has experienced tons of crude oil spill within their environment over the years and its impact on the environment is quite lethal. The soil is a major recipient of this spilled crude. When contaminated with crude oil, the load bearing capacity is consequently affected. This study aimed at providing a statistical evidence to prove that the impact of crude oil contamination on the soil＇s bearing capacity is significant. Four samples of uncontaminated soil of Kwale were collected and analyzed for their load bearing properties： cohesion （c）, angle of internal friction （θ°） and bulk density （γ）. These soil samples were polluted with crude oil in levels of 5%, 10%, 15% and 20% and compared with intact soil. A consistent reduction was observed in the bearing capacity as the crude oil level increased. Using the SPSS （statistically package for social sciences）, the significance was tested at the various contamination levels at a 5% confidence level and the result showed significance at 15% and 20% levels with calculated P-values of 0.038 and 0.035 respectively for both the square and strip foundation footings.
文摘The paper analyses the space time characteristics, primary causes and disastrous effects of the drying up of the Yellow River, and proposes the concept of "water resource bearing capacity (WRBC)", which refers to the maximum bearing capacity of a river in meeting human demands for water on the precondition of sound recycling of the ecosystem. The concept encourages cautious human actions to save and conserve water resources.
