Fire Protection Thickness Research Articles

강재단면형상을 고려한 소요 내화피복 두께 산정에 관한 연구

Abstract Surface area of the steel member exposed to fire differs according to type and size of the section and the kind of the member, which shows a big difference in the temperature rise of the steel by fire. The section factor (    ) is determined by factors such as type, size, and member of the steel and type of the fire protection material, and it is the criteria in determining thickness of the fire protection material. This study showed that the size of the steel increase regardless of the steel type, the section factor decrease. In the results on fire protection thickness of the steel according to the section factor, the efficiency of 1 hour fire protection was lower from 30 to 50% than the criteria. And there is the member, which have the thickness lower the minimum 27% in 2 hour fire protection, but it generally approached in the criteria. In case of H-shape steel, the efficiency of 3 hour fire protection was suitable for the criteria, but rectangular hollow steel section and circular hollow steel section were higher (5.0-17.5%) than the criteria.

Behavior of steel columns in a fire with partial damage to fire protection

Abstract An experimental study is performed on two specimens in a furnace to investigate the fire behaviour of steel columns with partial loss of fire protection. The steel columns are connected by flush end-plates at two ends and the axial load is kept constant with a load ratio of 0.55 subjected to an elevation of temperature. The specimens are protected with 20 mm thickness of fire protection. The damaged length of fire protection is 7% of the complete length of the column for specimen S-1 and 14% for S-2 at the two ends of the steel columns. The temperature of atmosphere around the specimens in the furnace is assumed to follow the ISO834 standard temperature and the temperatures and displacements are measured in the experiment. The temperature distribution along the steel column is modelled by finite element analysis and compared with the measured results. A continuum model is presented to predict the ultimate load capacity or critical temperature of the columns with fire protection damage. Analyses are carried out on the specimens and compared with the experiment. Experimental and analytical results showed that the fire resistance of steel columns with partial damage to the fire protection is reduced. The damage length of the fire protection has a great effect on the fire resistance of steel columns. The failure of the specimens mainly resulted from the buckling or yielding at the portion where the fire protection is damaged.

Developments in composite construction and cellular beams

This paper describes recent developments in composite construction and their effect on codified design procedures in the UK. Areas of particular interest include: rules on shear connection, design of beams with web openings, serviceability limits, such as floor vibrations, and fire safe design. The design of cellular beams with regular circular openings now includes generalized rules for web-post buckling, and for the development of in-plane moment in the web-post for asymmetric sections. Closed solutions for the maximum shear force due to limits on web-post bending or buckling are presented. The fire resistance of cellular beams is also dependent on the temperature of the web-post, and for closely spaced openings. It is necessary to increase the thickness of fire protection to the web. For serviceability design of beams, deflection limits and natural frequency and response factor for vibration are presented. It may be necessary to use stricter limits for certain applications.

Experimental Study and Calculation of Fire Resistance of Concrete-Filled Hollow Steel Columns

Hollow structural steel (HSS) columns filled with concrete offer a number of benefits and are often used in tall buildings and other industrial structures. A mathematical model was developed and used to investigate the influence of important parameters that determine the fire resistance of concrete-filled hollow steel columns. The behavior of concrete-filled HSS columns with or without fire protection subjected to axial or eccentric loads was experimentally investigated and the results presented in this paper. The parametric and experimental studies provide information for the development of formulas for the calculation of the fire resistance and fire protection thickness of the composite columns. The main objectives of this work were threefold: First, to report a series of fire tests on composite columns; second, to analyze the influence of several parameters, such as the sectional dimension, load eccentricity ratio, and fire protection thickness on the fire resistance of the composite columns. It was fo...

An experimental study and calculation on the fire resistance of concrete-filled SHS and RHS columns

Abstract The behavior of concrete-filled steel square hollow section (SHS) and rectangular hollow section (RHS) columns with or without fire protection subjected to axial or eccentric loads has been experimentally investigated and the results are presented in this paper. The parametric and experimental studies provide information for the development of formulas for the calculation of the fire resistance and the fire protection thickness of the composite columns. The main objectives of this paper were threefold: first, to report a series of fire tests on composite columns with square and rectangular sections. Secondly, to analyze the influence of several parameters, such as fire duration time, sectional dimension, slenderness ratio, load eccentricity ratio, strength of steel and concrete on the residual strength index (RSI) of the composite columns. Finally, to develop formulas for the calculation of the fire resistance and the fire protection thickness of the concrete-filled steel SHS and RHS columns, such formulas to be suitable for incorporation into building codes. The concepts of this paper were used to provide data on the necessary fire protection measures for the concrete-filled steel SHS columns used in a high-rise building, Ruifeng, Shangye Building in Hangzhou City, in southern China.

Experimental Study on Fire Resistance of Fire-Resistant Steel Beams.

This paper is to verify the fire resistance of beams made from fire-resistant(FR) structural steel by means of a full-scale loaded heat test. Because of the elements contained, FR Steel has higher strength than conventional structural steel at elevated temperatures. Its 0.2% proof stress at 600°C is equal to or greater than two-thirds the value specified at room temperature. Rockwool, ceramic fire protection, and foaming-type intumescent coating were used as fire-protection materials. The results showed that the fire-protection thickness can be reduced below what is required for conventional steel beams and that 1-h fire resistance can be obtained by intumescent coating with a lower insulation property.

Effects of structural continuity on fire resistant design of steel columns in non-sway multi-storey frames

Abstract This paper discusses two aspects of the effect of structural continuity on the fire resistant design of steel columns in non-sway multi-storey steel frames. One is beneficial and the other is detrimental. The beneficial effect is to enhance the rotational restraint to the column and thus to reduce its effective length and increase its load carrying capacity. The detrimental effect is to increase the column compressive load due to axial restraint to its thermal expansion. This paper attempts to put forward a simple design method to reconcile these two effects. A comprehensive parametric study is performed to evaluate these two effects on the column limiting temperature and its fire protection thickness. It is found from the results of this parametric study that for buildings with a practical range of axial restraint to columns, these two effects almost cancel each other out. This paper therefore proposes that for the calculation of column limiting temperature, the additional compressive force in the column may be discarded provided the original column slenderness ratio at the cold condition is used for elevated temperature design. The fire protection thickness of the column may be conservatively obtained by increasing by 20% that calculated using the above limiting temperature.

The Approach to Passive Fire Protection Design for the North Everest and Lomond Platforms

Abstract Traditional methods of determining the extent and thickness of passive fire protection (PFP) on offshore platform structures are simplistic and provide little opportunity for design optimization. This paper presents a review of alternative methods of determining the use of PFP which have been tried to overcome these disadvantages. The method progressed and used for North Everest and Lomond was based upon the modeling of credible fire scenarios, the calculation of steel temperatures and the progressive collapse analysis of topsides structure under rising temperature. The selected method allowed the design engineer to optimize the use of PFP while instilling confidence that the design met specified safety objectives.

The application of BS5950: Part 8 of fire limit state design to the performance of ‘old’ structural mild steels

An investigation has been carried out to extend the guidance given in the new British Standard BS5950: Part 8, on fire limit state design, to the refurbishment and fire damage reinstatement of old steel framed, buildings. Structural mild steel produced to BS15 approximately 50 years ago was found to be generally weaker at elevated temperatures than its modern counterpart—BS4360: Grade 43A (BS EN 10025: Grade 430A). However, providing in design calculations due recognition is given to the lower yield stress of old mild steel at ambient temperature, its performance in fire will be as good as that being currently produced. For the present time, it is therefore appropriate to adopt the same relationships between strength, loading and temperature for structural members given in the new Code, with no additional penalties on fire protection thickness should this be necessary. Fire simulation treatments on steel manufactured to BS15 demonstrated that the degradation in strength properties is in agreement with work reported earlier on ‘weak’ mild steel—BS4360: Grade 43A. The results of a similar evaluation on mild steel produced since the 1986 revision of BS4360: Grade 43A are also in line with previous work.