Question
In heat of hydration analysis, self-weight is not considered for each construction stage.
Answer
In hydration heat analysis, self-weight is not considered when analyzing each stage. Even if the self-weight is included in the construction stage, it will not be considered if the 'Include Selfweight Load' option is checked off.
The increase in the size and rapid construction of concrete structures has led to the frequent occurrence of significant cracks in the structure due to thermal stress caused by the hydration heat of cement. Previously, it was thought that such phenomena occurred only in concrete structures with particularly large dimensions, but thermal cracks caused by hydration heat are common in relatively small structures depending on the materials used and construction conditions. Therefore, it is necessary to define the conditions that may cause thermal cracks due to hydration heat as mass concrete and conduct a review of the thermal stress and cracks caused by cement hydration.
Thermal cracks occur in the early stages of construction and can cause a reduction in internal forces, water tightness, and long-term durability of the structure. Therefore, thorough examination should be carried out during the design, construction, and management stages to prevent such cracks. Moreover, large concrete structures are not cast all at once but are divided and cast in sections, resulting in concrete with different heating characteristics and time-dependent properties. Therefore, to build an analysis model which is similar to the real structure, the model should be considered the construction stages.
In midas Civil, there is an option called 'Include Selfweight Load' in the 'Heat of Hydration Analysis Control' when anlaysing with hydration heat.
If 'Include Selfweight Load' is checked off, the self-weight will not be considered even if the selfweight load is included in each construction stage of the hydration heat analysis.
However, if the 'Include Selfweight Load' is checked on, even when the self-weight load is not included in the construction stage, the self-weight load will be considered in the analysis.