Numerical Analysis Of Fire Resistance About Ancient Timber Structure

In order to study fire resistance of timber structure,that different parameters impact on charing rate of wood members was analyzed.Temperature field distribution of post and lintel construction,and charring rule of mortise-tenon joint were simulated.That different factors impact on fire endurance of tensile wood members was analyzed.Research status about fire resistance of timber structures,characteristics of ancient timber structure,fundamental principles about analysis of both heat transfer and thermal stress were introduced.Through comparative analysis methods of both numerical computation and experiment to verify numerical analysis was accurate.Fire resistance of ancient timber structure was numerically simulated by concrete model at last.The specific contents are roughly as follows:1)Using finite element software ABAQUS simulated that different factors,such as density,water content and size effect,impact on charing rate of wood members in the fire.The numerical results show that density has an obvious effect on charing rate of wood compared with both water content and size effect;and charing rate of timber takes on a trend that decrease firstly,then increase and decrease again for a time of fire.2)According to temperature field analysis of wood members in the fire,a trend of temperature was simulated about wood members in the fire.The results indicated that temperature trend curve shows stable variation of temperature platform at 100 degrees centigrade;and the farther fire surface is,the longer temperature platform becomes;as the distance of fire surface increases continually,it's temperature decrease gradually at same moment.3)Temperature field of a post and lintel construction was simulated in the fire.The results of analysis indicated that charing rate of vertical direction is greater than charing rate of horizontal direction;both tenon and mortice of dovetail joint at narrow end have various degrees of charring,but contact surface of both mortise and tenon doesn't appear obvious charring.4)That load level impacts on fire endurance of axial wood members was simulated,and that eccentricity impacts on fire endurance of biasing wood members was simulated.The results of analysis indicated that fire endurance of tensile wood members presents decreasingtrend with enlargement of load level under a certain conditions;eccentricity of loading has an obvious impact on fire endurance of biasing wood members,and fire endurance of wood members decreases with enlargement of eccentricity on one condition.