oSIST ISO/DIS 28842:2010

INTERNATIONAL ISO
STANDARD 28842
First edition
2013-06-15

Guidelines for the simplified design of
reinforced concrete bridges
Lignes directrices pour la conception simplifiée des ponts en béton
armé





Reference number
ISO 28842:2013(E)
©
ISO 2013

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ISO 28842:2013(E)

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©  ISO 2013
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ISO 28842:2013(E)
Contents Page
Foreword . v
Introduction . vi
1  Scope . 1
2  Normative references . 1
3  Terms and definitions . 2
4  Symbols and abbreviated terms . 13
5  Design and construction procedure . 18
5.1  Procedure . 18
5.2  Design documentation . 20
6  General Guides . 20
6.1  Limitations . 20
6.2  Limit states . 23
6.3  Ultimate limit state design format . 25
6.4  Serviceability limit state design format . 26
7  Structural systems and layout . 26
7.1  Description of the components of the structure . 26
7.2  General program . 27
7.3  Structural layout . 28
7.4  Feasibility under the guidelines . 29
8  Actions (Loads) . 30
8.1  General . 30
8.2  Dead loads . 30
8.3  Live loads . 31
8.4  Longitudinal forces . 33
8.5  Earth pressure . 33
8.6  Wind loads . 34
8.7  Earthquake inertial forces . 34
8.8  Thermal Forces . 44
8.9  Load combinations . 46
9  Design requirements . 46
9.1  Scope . 46
9.2  Additional requirements . 46
9.3  Materials for structural concrete . 47
9.4  Concrete Mixture Proportioning . 48
9.5  Development length, lap splicing and anchorage of reinforcement . 57
9.6  Limits for longitudinal reinforcement . 59
9.7  Minimum amounts of transverse reinforcement . 62
10  Superstructure . 66
10.1  Strength of members subjected to flexural moments . 66
10.2  Strength of members subjected to shear stresses . 72
10.3  Decks . 76
10.4  Solid slabs supported on girders, beams, or joists . 83
10.5  Girders, beams and joists . 103
10.6  Railings . 119
11  Substructure . 120
11.1  Girders that are part of a frame . 120
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ISO 28842:2013(E)
11.2  Strength of members subjected to axial loads with or without flexure . 128
11.3  Torsion . 132
11.4  Bearing strength . 133
11.5  Columns and Piers . 133
11.6  Concrete walls . 142
12  Foundations . 150
12.1  Foundation type and capacity . 150
12.2  Subsurface exploration and testing programs . 151
12.3  Dimensioning of the foundation elements . 151
12.4  Footings . 151
12.5  Foundation mats . 153
12.6  Footings on piles . 153
12.7  Foundation beams . 154
12.8  Retaining Walls . 154
13  Lateral load resisting system . 163
13.1  General . 163
13.2  Specified lateral forces . 164
13.3  Lateral force resisting structural system . 164
13.4  Minimum amount of structural concrete walls . 164
13.5  Special reinforcement details for seismic zones . 165
14  Bearings . 176
14.1  General . 176
14.2  Multiple roller bearings . 176
14.3  Elastomeric bearings . 177
14.4  Anchorage . 179
14.5  Design forces for supporting structure . 179
Annex A (normative) Equivalent equations for material factors . 181
Annex B (normative) Beam Deflection . 186
Bibliography . 187

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ISO 28842:2013(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of
ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2. www.iso.org/directives
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent
rights identified during the development of the document will be in the Introduction and/or on the ISO list of
patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
The committee responsible for this document is ISO/TC 71, Concrete, reinforced concrete and pre-stressed
concrete, Subcommittee SC 5, Simplified design standard for concrete structures.
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ISO 28842:2013(E)
Introduction
The aim of this International Standard is to provide rules for the design and construction of relatively short
span concrete bridges. This International Standard is developed for countries that do not have existing
national standards on this subject and to offer to local regulatory authorities an alternative for the design of
relatively small bridges that abound in urban overpasses and over creeks and rivers everywhere. This
International Standard shall not be used in place of a national standard unless specifically considered and
accepted by the national standards body or other appropriate regulatory organization. The design rules are
based in simplified worldwide-accepted strength models. This International Standard is self-contained;
therefore, loads, simplified analysis procedures and design specifications are included, as well as minimum
acceptable construction practice guidelines.
The minimum dimensional guidelines contained in this International Standard are intended to account for
undesirable side effects that will require more sophisticated analysis and design procedures. Material and
construction guidelines are aimed at site-mixed concrete as well as ready-mixed concrete, and steel of the
minimum available strength grades.
The earthquake resistance guidelines are included to account for the numerous regions of the world which lie
in earthquake prone areas. The earthquake resistance for zones with high seismic hazard is based upon the
employment of structural concrete walls (shear walls) that limit the lateral deformations of the structure and
provide for its lateral strength, in place of piers or frames that can be used in zones with intermediate, low or
no significant earthquake hazard.
This International Standard contains guidelines that can be modified by the national standards body due to
local design and construction requirements and practices. These guidelines that can be modified are included
using ["boxed values"]. The authorities in each member country are expected to review the "boxed values"
and may substitute alternative definitive values for these elements for use in the national application of the
document.
A great effort was made to include self-explanatory tables, graphics, and design aids to simplify the use of this
International Standard and provide foolproof procedures. Notwithstanding, the economic implications of the
conservatism inherent in approximate procedures as a substitute for sound and experienced engineering
should be a matter of concern to the designer that employs the document, and to the owner that hires him.

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INTERNATIONAL STANDARD ISO 28842:2013(E)

Guidelines for the simplified design of reinforced concrete
bridges
1 Scope
This International Standard can be used as an alternative to the development of a National Concrete Bridge
Design and Construction Code, or equivalent document in countries where no national design codes are
available by themselves, or as an alternative to the National Concrete Bridge Design and Construction Code
in countries where specifically considered and accepted by the national standards body or other appropriate
regulatory organization, and applies to the planning, design and construction of structural concrete bridges to
be used in new bridges of restricted span length, height of piers, and type.
The purpose of these guidelines is to provide sufficient information to perform the design of the structural
concrete bridge that complies with the limitations established in 6.1. The rules of design as set forth in this
International Standard are simplifications of more elaborate requirements.
Although the guidelines contained in this International Standard were drawn to produce, when properly
employed, a structural concrete structure with an appropriate margin of safety, these guidelines are not a
replacement for sound and experienced engineering. In order for the resulting structure designed employing
these guidelines to attain the intended margin of safety, this International Standard must be used as a whole
and alternative procedures should be employed only when explicitly permitted by the guidelines. The minimum
dimensioning guides as prescribed in this International Standard replace, in most cases, more elaborate
procedures such as those prescribed in the National Code, and the possible economic impact is compensated
for by the simplicity of the procedures prescribed here.
The professional performing the structural design under these guidelines should meet the legal requirements
for structural designers in the country of adoption and have training and a minimum appropriate knowledge of
structural mechanics, statics, strength of materials, structural analysis, and reinforced concrete design and
construction.
Designs and details for new bridges should address structural integrity by considering the following:
- the use of continuity and redundancy to provide one or more alternate paths;
- structural members and bearing seat widths that are resistant to damage or instability;
- external protection systems to minimize the effects of reasonably conceived severe loads.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 679, Cement — Test methods — Determination of strength
ISO 863, Cement — Test methods — Pozzolanicity test for pozzolanic cements
ISO 3010, Basis for design of structures — Seismic actions on structures
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ISO 28842:2013(E)
ISO 4354, Wind actions on structures
ISO 6274, Concrete — Sieve analysis of aggregates
ISO 6782, Aggregates for concrete — Determination of bulk density
ISO 6783, Coarse aggregates for concrete — Determination of particle density and water absorption —
Hydrostatic balance method
ISO 6934-1, Steel for the prestressing of concrete — Part 1: General requirements
ISO 6934-3, Steel for the prestressing of concrete — Part 3: Quenched and tempered wire
ISO 6934-4, Steel for the prestressing of concrete — Part 4: Strand
ISO 6934-5, Steel for the prestressing of concrete — Part 5: Hot-rolled steel bars with or without subsequent
processing
ISO 6935-1, Steel for the reinforcement of concrete — Part 1: Plain bars
ISO 6935-2, Steel for the reinforcement of concrete — Part 2: Ribbed bars
ISO 6935-3, Steel for the reinforcement of concrete — Part 3: Welded fabric
ISO 7033, Fine and coarse aggregates for concrete — Determination of the particle mass-per-volume and
water absorption — Pycnometer method
ISO 9194, Bases for design of structures — Actions due to the self-weight of structures, non-structural
elements and stored materials — Density
ISO 9597, Cement — Test methods — Determination of setting time and soundness
ISO 10144, Certification scheme for steel bars and wires for the reinforcement of concrete structures
ISO 3766:2003, Construction drawings — Simplified representation of concrete reinforcement
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
abutment
end support of a bridge superstructure
NOTE Abutments are used to transmit the reaction of superstructure to the foundations, to retain the earth filling and
to connect the superstructure to the approach roads.
3.2
acceleration of gravity, g
acceleration produced by gravity at the surface of the earth
2
NOTE For the application of these guidelines its value can be approximated to g ≈ [10] m/s .
3.3
admixture
material other than water, aggregate, or hydraulic cement, used as an ingredient of concrete and added to
concrete before or during its mixing to modify its properties
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ISO 28842:2013(E)
3.4
aggregate
granular material, such as sand, gravel, crushed stone, and iron blast-furnace slag, used in conjunction with a
cementing medium to form a hydraulic cement concrete or mortar
3.5
anchorage
device used to anchor a non-structural element to the structural framing
3.6
backfill
material used for refilling any hole that has been excavated
3.7
bar diameter, nominal
approximate diameter of a steel reinforcing bar, often used as a class designation
NOTE For deformed bars, it is common practice to use the diameter of a plain bar having the same area.
3.8
beam
horizontal, or nearly horizontal, structural member supported at one (such as a cantilever) or more points, but
not throughout its length, transversely supporting a load, and subjected primarily to flexure
3.9
bearing capacity of the soil
maximum permissible stress on the foundation soil that provides adequate safety against bearing failure of the
soil, or settlement of the foundation of such magnitude as to impair the structure
NOTE Its value is defined at the working stress level.
3.10
bearing – elastomeric
device constructed partially or wholly from elastomer to transmit loads and accommodate movements
between a bridge and its supporting structure
3.11
bending moment
product of a force and the distance to a particular axis, producing bending effects in a structural element
3.12
boundary elements
portions along wall edges strengthened by longitudinal and transverse reinforcement
NOTE Boundary elements do not necessarily require an increase in thickness of the wall.
3.13
bridge
structure carrying a road, path or railway over an obstacle
3.14
caisson
foundation pile of large diameter, built partly or totally above ground and sunk below ground usually by digging
out the soil inside
3.15
cantilever
element that extends beyond its support and is supported on one end only
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ISO 28842:2013(E)
3.16
cement
material as specified in the corresponding referenced ISO standards, which, when mixed with water, has
hardening properties
NOTE Used either in concrete or by itself.
3.17
clearance
distance by which one thing clears another; the space between them
3.18
column
vertical member used primarily to support axial compressive loads
3.19
collector elements
elements that serve to transmit the inertia forces within the diaphragm to members of the lateral-force resisting
system
3.20
combined footing
footing that transmits to the supporting soil the load carried by several columns or structural concrete walls
3.21
compression reinforcement
reinforcement provided to resist compression stresses induced by flexural moments acting on the member
section
3.22
concrete
mixture of portland cement and any other hydraulic cement, fine aggregate, coarse aggregate, and water, with
or without admixtures
3.23
concrete mix design
choice and proportioning of the ingredients of concrete
3.24
'
concrete specified compressive strength, f
c
compressive cylinder strength of concrete used in design and evaluated in accordance with the appropriate
ISO standard, expressed in megapascals (MPa)
' '
NOTE Whenever the quantity f is under a radical sign ( f ), the positive square root of numerical value only is
c c
intended, and the result has units of megapascals (MPa).
3.25
confinement hook
hook on a stirrup, hoop, or crosstie having a bend not less than 135° with a six-diameter (but not less than
75 mm) extension that engages the longitudinal reinforcement and projects into the interior of the stirrup or
hoop
3.26
confinement stirrup or tie
closed stirrup, tie or continuously wound spiral
NOTE A closed stirrup or tie can be made up of several reinforcement elements each having confinement hooks at
both ends. A continuously wound spiral should have a confinement hook at both ends.
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ISO 28842:2013(E)
3.27
corrosion
gradual removal or weakening of metal from its surface that requires the presence of humidity and oxygen,
and is helped by the presence of other materials
3.28
cover, concrete
thickness of concrete between surface of any reinforcing bar and the nearest face of the concrete member
3.29
crosstie
continuous reinforcing bar having a 135° hook at one end and a hook not less than 90° at least a six-diameter
extension at the other end
NOTE The hooks should engage peripheral longitudinal bars. The 90° hooks of two successive crossties engaging
the same longitudinal bars should be alternated end for end.
3.30
crown
highest point of a convex structure, such as an arch or a vault
3.31
curb
edge where a raised pavement/sidewalk/footpath, road median, or road shoulder meets an unraised street or
other roadway
3.32
curing
keeping the concrete damp for a period of time, usually several days, starting from the moment it is cast, in
order for the cement to be provided with enough water to harden and attain the intended strength
NOTE Appropriate curing will greatly reduce shrinkage, increase strength of concrete, and should reduce surface
cracking. Curing time will depend on temperature and relative humidity of surrounding air, the amount of wind, the direct
sunlight exposure, the type of concrete mix employed, and other factors.
3.33
deformed reinforcement
steel reinforcement that has deformations in its surface to increase its bond to the concrete.
NOTE The following steel reinforcement should be considered deformed reinforcement under these guidelines:
deformed reinforcing bars, deformed wire, welded plain wire fabric, and welded deformed wire fabric conforming to the
appropriate ISO standards.
3.34
depth of member, h
vertical size of a cross section of a horizontal structural element
3.35
design load combinations
combinations of factored loads and forces as specified in these guidelines
3.36
design strength
product of the nominal strength multiplied by a strength reduction factor
3.37
development length
length of embedded reinforcement required to develop the design strength of reinforcement at a critical
section
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ISO 28842:2013(E)
3.38
development length for a bar with a standard hook
shortest distance between the critical section (where the strength of the bar is to be developed) and a tangent
to the outer edge of the 90° or 180° hook
3.39
differential settlement
when the foundation of different parts of a structure settle different amounts
3.40
drainage
natural or artificial removal of surface and sub-surface water from a given area
NOTE Drainage is a system that carries water or sewage away from a place.
3.41
durability
characteristic of a structure to resist gradual degradation of its serviceability in a given environment for the
design service life
3.42
effective depth of section, d
distance measured from extreme compression fiber to centroid of tension reinforcement
3.43
embedment length
length of embedded reinforcement provided beyond a critical section
3.44
factored loads and forces
specified nominal loads and forces multiplied by the load factors prescribed in
...