The standard outlines the nominal sizes, weights, and sectional characteristics of hot-rolled and slit steel tee bars employed in structural applications. It includes various categories such as normal, deep legged, and slit types derived from light and medium weights, as well as those made from H-section steel. This specification is vital for producers, fabricators, and design engineers working within Indian steel construction practices.
Overview
The standard outlines the nominal sizes, weights, and sectional characteristics of hot-rolled and slit steel tee bars employed in structural applications. It includes various categories such as normal, deep legged, and slit types derived from light and medium weights, as well as those made from H-section steel. This specification is vital for producers, fabricators, and design engineers working within Indian steel construction practices.
Audience
Contents
Structure
This section defines the scope of the standard, detailing the nominal sizes, weights, and sectional data for hot rolled and slit steel tee bars used in structural engineering. It introduces the classification system including normal, deep legged, slit light and medium weights, and slit tee bars derived from H-sections. The section also explains key sectional properties such as area, weight, moments of inertia, section moduli, centroid positions, radii of gyration, and the angle between the web and flange. Rounding conventions per IS 2-1960 are highlighted, and the relationship with IS 808 for medium weight sections is noted.
Defines the letter symbols and terms used throughout the standard, including sectional area (a), calculated weight (w = 0.785 × a), centroid distances (Cxx), moments of inertia (Ixx, Iyy), extreme fibre distances (exx, eyy), section moduli (Zx, Zy), radii of gyration (rxx, ryy), and flange-web angle (D). It also clarifies the classification abbreviations such as NT, DT, LT, MT, and HT.
Details the key symbols and their meanings with the corresponding units and formulas. Weight per meter is calculated by multiplying sectional area by 0.785. Section moduli are derived by dividing moments of inertia by extreme fibre distances. Radii of gyration are determined by the square root of the ratio of moment of inertia to sectional area. Abbreviated reference symbols for different tee bar classifications are also provided.
Outlines the different categories of tee bars covered under the standard: Normal Tee Bars (NT), Deep Legged Tee Bars (DT), Slit Light Weight Tee Bars (LT), Slit Medium Weight Tee Bars (MT), and Slit Tee Bars from H-Sections (HT). The classification aids in identifying the shape, weight, and manufacturing method of the tee bars.
Lists nominal dimensions and key sectional properties such as sectional area, weight, centroid location, moments of inertia, radii of gyration, and section moduli for various tee bar sizes. The section highlights the formulae used and includes notes on rounding rules and unit conventions.
Specifies that dimensional tolerances for tee bars must comply with IS 1852:1973, which governs rolling and cutting tolerances for hot-rolled steel products. Typical tolerance ranges for thickness, width, and length are summarized. The importance of adhering to these tolerances for interchangeability and manufacturing consistency is emphasized.
Describes the abbreviations used for shop marking and drawings to identify tee bar classifications clearly, ensuring consistent communication between fabricators, manufacturers, and designers. It also reiterates the key letter symbols and formulas relevant for marking.
Discusses manufacturing parameters, detailing sectional properties such as size, thickness, radii, and centroid positions for Indian Standard tee bars. It includes notes on how dimensions align with IS 808 and the rounding off protocols per IS 2-1960. Abbreviated symbols used in trade and production are also covered.
Highlights related Indian Standards essential for understanding and applying IS 1173, including IS 808 (Part I) for beam dimensions, IS 1852 for tolerances, and IS 2 for rounding rules. It also provides a summary of classification abbreviations used within the standard.
Presents key formulas and tabulated nominal dimensions, weights, and sectional properties for various tee bar designations. The annexures provide detailed numerical data on sectional areas, weights, sizes, thicknesses, radii, centroid locations, moments of inertia, radii of gyration, and section moduli to assist in design and fabrication.
Frequently Asked
The standard specifies nominal dimensions and weights for five tee bar categories: Normal (ISNT), Deep Legged (ISDT), Slit Light Weight (ISLT), Slit Medium Weight (ISMT), and Slit from H-Sections (ISHT). Each type includes defined leg lengths, widths, thicknesses, and corresponding weights given in kilograms per meter. These details are tabulated in Table 1 of the standard and are essential for structural design and manufacturing.
Hot rolled and slit tee bars are categorized into five groups: Rolled Normal Tee Bars (ISNT), Rolled Deep Legged Tee Bars (ISDT), Slit Light Weight Tee Bars (ISLT), Slit Medium Weight Tee Bars (ISMT), and Slit Tee Bars produced from H-Sections (ISHT). The classification differentiates bars based on their cross-sectional shape, manufacturing process (rolled or slit), and weight category.
Dimensional tolerances for tee bars must conform to IS 1852:1973, which sets permissible deviations for thickness, width, and length of hot-rolled steel sections. Typical tolerance ranges include ±0.5 mm for thickness, ±1.0 mm for width, and ±5 to 10 mm for length, depending on specific sizes. These tolerances ensure consistency and quality in manufacturing.
The standard provides detailed sectional properties including sectional area, weight, centroid location from the flange, moments of inertia about principal axes (Ixx and Iyy), radii of gyration (rxx and ryy), and section moduli (Zx and Zy). These properties are essential for structural analysis and design of tee bars.
IS 1173 focuses specifically on hot rolled and slit tee bars, while IS 808 covers rolled steel beams, channels, and angle sections. The medium weight tee bars initially included provisionally in IS 1173 have been standardized under IS 808 (Part I) - 1973. Thus, IS 1173 complements IS 808 by providing detailed specifications for tee bars, ensuring uniformity and compatibility in steel structural sections.
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