What is IS code 456:2000 in civil engineering?
Purpose and Scope
This code covers general structural use of plain and
reinforced concrete in buildings and civil engineering works, including
requirements for materials, workmanship, inspection, testing, and the design
and construction process.
Major Sections and Key Contents
Section 1: General
Scope, references, definitions, terminology, and symbols
used.
Section 2: Materials, Workmanship, Inspection, Testing
Materials (cement, aggregates, water, reinforcement,
admixtures), storage, grades and properties of concrete, workability,
durability, mix proportioning, batching, mixing, quality assurance.
Detailed requirements for concrete durability based on
environmental exposure (such as minimum cover for reinforcement, maximum
water-cement ratio, minimum cement content).
Section 3: General Design Considerations
Design aims, loading (dead, live, wind, earthquake), fire
resistance, analysis, structural stability, serviceability requirements, and
rules for load combinations.
Recommendations for effective span, stiffness, sway/no sway
in columns, and modification factors for tension reinforcement.
Section 4: Special Design Requirements
Specific structural members (beams, slabs, columns,
footings), including minimum and maximum reinforcement, curtailment, deflection
control, shear strength calculations, detailing, and lap lengths.
Specific provisions on staircases, walls, and
water-retaining structures.
Section 5: Structural Design
Guidance for Limit State Design and Working Stress methods,
with design examples and allowable stresses.
Acceptance criteria for concrete strength, sampling, and
testing of concrete (compressive strength test requirements, minimum
frequency).
Supervision, quality assurance, amendments, and construction
joints.
Important Clauses and Design Rules
Material Selection and Requirements: Clauses 5.1–5.6 specify
cement types, aggregate size, water quality (pH, solids limits), and
reinforcement standards.
Cover to Reinforcement: Table 16 (minimum nominal
cover for durability: 20–75 mm depending on exposure).
Column Design: Clauses 25 and 39 (classification,
slenderness, minimum/maximum reinforcement, column bending design).
Durability: Clause 8 sets out rules for materials,
cover, and mix proportions under different environmental exposures.
Mix Proportioning: Design and nominal mix
requirements for varying grades of concrete for structural and non-structural
use.
Formwork and Curing: Clauses 11, 13 on proper
formwork stripping time, joint treatment, compaction, and curing methods.
Construction Joints and Quality Assurance: Focus on
joint placement, inspection, and continuous supervision to maintain quality.
Acceptance Criteria: Clauses 15 and 16 (sampling, frequency, test results, acceptance limits for compressive strength)
