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COMMENTS ON THE PRACTICAL USE OF EUROCODE 8
Article · January 1999
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2. COMMENTS ON THE PRACTICAL USE
OF EUROCODE 8
BRITO, J. DE ; LOPES, M. S.
1

3. COMMENTS ON THE PRACTICAL USE OF EUROCODE 8
Authors Jorge Manuel Caliço Lopes de Brito (1)
and Mário Manuel Paisana dos Santos
Lopes (1)
(1)
Professional position: Assistant Professor
Address: Instituto Superior Técnico – Departamento de Engenharia Civil
Av. Rovisco Pais 1000 Lisboa Portugal
Tel: 351 1 8418212 / 354
Fax: 351 1 8497650
Email: jb@civil.ist.utl.pt
2

4. COMMENTS ON THE PRACTICAL USE OF EUROCODE 8
Brito, J. de and Lopes, M. S.
SUMMARY
Some comments and suggestions for improvement concerning the most important
global issues introduced or developed by Eurocode 8 (such as capacity design, local
ductility, structural regularity criteria and ductility demands) are presented. The practical
application of the clauses regarding these aspects shows that considerable difficulties
may be encountered by structural designers, both in terms of time and additional effort.
Furthermore, some dimensions and reinforcement ratios imposed by these rules have
proved to be very conditioning in terms of architectural compatibility, economic
feasibility and on site working procedures.
KEYWORDS
Eurocode 8, capacity design, ductility, concrete buildings
3

5. COMMENTS ON THE PRACTICAL USE OF EUROCODE 8
1. INTRODUCTION
The existence of common unified rules for structural design in the European Union,
the Eurocodes, is expected to provide structural designers and construction companies
with new opportunities, as well as lead to substantial savings due to the globalisation of
companies business and markets. This process may be enhanced, and the corresponding
advantages increased, by the eventual adoption (partially or fully) of the Eurocodes by
neighbouring countries in North Africa and Eastern Europe, as well as other countries
with strong economic and cultural ties with European countries. It is therefore of the
utmost importance that the practical implementation of the Eurocodes is successful.
In what regards Eurocode 8 (EC8), the whole process of building and improving the
code has focussed on the scientific side. This has led to a document that, notwithstanding
the critics and comments that can be made, is extremely sophisticated and advanced, a
state-of-art in some issues. However, this has also given rise to a document that in some
parts is too complex. This is by no means a condition for its success, quite the contrary.
In many situations, the practical consequence of the code’s extreme complexity is the
difficulty of application. This may lead to an unsuccessful implementation of the code
in current design practice and may be a deterrent for other countries that would
otherwise tend to use it.
In this paper some important issues dealt with in EC8 - Part 1 - General Rules and
Rules for Buildings [1], are discussed, with special emphasis on some of the aspects
with possible negative consequences at the level of the practical application of the code.
The range of the comments and suggestions is limited to concrete current buildings.
2. APPLICATION OF CAPACITY DESIGN PRINCIPLES
The capacity design concept is one of the great advances EC8 will bring to European
design practice, since as compared with existing codes, it is either a new concept or it
represents a development of concepts already embodied implicitly in some codes.
However, the practical implementation of capacity design principles, as embodied in
EC8, is somewhat complex.
4

6. One of the most clear cases of the above mentioned situation can be found in clause
2.8.1.1.1 of Part 1-3 of EC8. The columns design moments are evaluated as a function of
a set of moments determined from the analysis, with the respective signs, as shown in
Fig. 1.
+
+
+
+
αCD,1 = γRd
MARd1+MBRd1
|MCSd1-MDSd1|;
1 MCSd1
MSd1,C=αCD,
αCD,2 = γRd
MARd2+MBRd2
|MCSd2-MDSd2|; 2 MCSd2
MSd2,C=αCD,
Figure 1 [1] - Evaluation of design moments in columns according to EC8
However, standard dynamic analyses only provide non-balanced non-simultaneous in
time maximum values of those moments. This leads to ambiguities and complexities in
the design process. These are difficult to avoid without leading to over-conservative
design of the columns (i.e. by using only the actual resisting moments of the beam-ends
near the joints, and their most adverse combination).
Incompatibilities with the architectural design arise due to the fact that the above
provisions lead to columns with flexural capacity above the capacity of the connecting
beams. In order to meet the criteria mentioned above in two orthogonal directions,
columns need to have large dimensions in both directions.
However, the objective of avoiding the formation of plastic hinges at the columns is
questionable in some structures. This is intended to prevent the formation of soft storey
mechanisms, such as the one shown in Fig. 2a). By preventing the formation of plastic
hinges in the columns, a mechanism with a higher energy dissipation capacity is obtained.
However, building structures have more than just one single frame. Each frame interacts
with the other frames and/or walls. In dual frame-wall buildings in which, according to
capacity design principles, plastic hinges on the walls are only allowed to take place at
their base, the formation of plastic hinges in both ends of all the columns in the same
C
D
B A
MCSd1
MDSd1
MARd1
MBRd1
C
D
B A
MCSd2
MDSd2
MARd2
MBRd2
5

7. storey is acceptable. Fig. 3 illustrates this principle, showing that the spreading of
plasticity along the frame before the structure becomes a mechanism may be similar,
regardless of the fact that the hinges in the frame take place in the columns or in the
beams.
a) Soft storey mechanism b) Formation of plastic hinges in the beams
Figure 2 - Formation of plastic hinges in a frame
a) Formation of hinges in the beams b) Formation of hinges in the columns
Figure 3 - Formation of hinges in a frame integrated in a dual frame-wall system
It is suggested that these clauses should only apply to frame buildings and, at the
most to a lesser extent, to dual frame-wall buildings, where the walls are responsible for
a reasonable part of the overall seismic resistance and plastic hinges are only allowed at
the ground level.
The application of capacity design principles to walls (clause 2.11.1.3) has the
shortcoming of assuming a bending moment diagram of a cantilever loaded
perpendicularly to its longitudinal axis, as shown in Fig. 4 (on the left). In fact, the
bending moment diagram in a structural wall of a real building may not follow the
idealised diagram, due to two main reasons:
6

8. • the existence of basements - In this case, the diagram on the left of Fig. 4 can be
representative of the real diagram only above the ground level, and the criterion
proposed for the design envelope can be applied to this region;
• the foundations deformability in tall buildings without basements - Even though
this may not correspond to a good global design, structural designers often do not
have a choice in these issues, which are decided at the level of architectural and
urban design. In this type of structure, the maximum bending moment may not
take place at ground floor level, as represented by line “a” in Fig. 4 (on the right),
due to the deformability of the foundations. The qualitative change in the design
envelope for bending moments shown in line “b” on the right of Fig. 4 is proposed.
Figure 4 - Design envelopes for bending moments in slender walls: according to EC8 on
the left; proposed for flexible foundations
With regard to the shear force diagrams, similar comments can be made about the
influence of basements or about the deformability of foundations on the location of the
maximum shear force. It is suggested that, for buildings with basements, the shear
forces envelope proposed by EC8 applies only to the part of the wall above the ground
floor and that, for buildings without basements and with flexible foundations, the EC8
design envelope is changed as shown in Fig. 5b).
3. LOCAL DUCTILITY
a
a
b
b
a – elastic analysis
b – design envelope
ground level
b
a
7

9. The question of local ductility, defined in clause 2.4.4, is one of the most important
issues in Part 1-3 of EC8, under the specific rules for concrete buildings. Critical regions
(“plastic hinges”), where high plastic rotational capacities must be guaranteed in order
to increase the overall ductility of the structure, are subject to a complete new set of
rules, that are additional to the ones included in EC2. These rules, concerning mostly
geometric limitations and detailing procedures, complement the capacity design
philosophy through an efficient confinement of concrete in those regions. However, the
practical results of these theoretically sound clauses can be either overly conservative,
expensive and/or hard to implement at the construction site.
2/3 h
1/3 h
Vwall,top>Vwall,max /2
Design
envelope
hw
a
b
c
Vwall,max
h - height above the level of Vmax
hw - height above ground level
a) According to EC8 b) Proposed
Figure 5 - Shear force design envelope
The proposed minimum volumetric ratio values of confining hoops in the critical
regions of columns (clauses 2.8.2 to 2.8.4) and walls boundary elements (clause 2.11.2.3)
represent, for all ductility classes, a very significant increase over the nowadays current
values. This is, up to a point, a welcome change as it has been proved that the lack of
proper confinement reinforcement, namely near beam-column joints, is one of the main
causes for the collapse of concrete structures during earthquakes. However, for medium
and high ductility class structures, it has been shown [2] that the levels of shear reinfor-
cement are such that, at the construction site, it is practically impossible to position such
2/3 hw
1/3 hw
Vwall,top>Vwall,base /2
Vwall,base
Design
envelope
a - diagram obtained from elastic analysis
b - diagram corrected by amplifying factor ∈
defined in clause 2.11.1.3(5)b
c - design diagram VSd
ground level
a
b
c
c
b
a
8

10. a high density of bars and then cast and vibrate properly the concrete. This results from
the imposition of complex multiple hoop patterns with a spacing that can be as small as 6
cm and a hoop bar diameter of 10 mm in relatively small transverse sections.
The complexity of the calculation process (clause 2.8.1.3) is another worrisome
aspect from this set of rules. The minimum confinement reinforcement ratio depends
simultaneously and non linearly on the hoop pattern, the normalised axial force and the
hoop spacing. Therefore, the process results long and iterative. More importantly, even
in low ductility structures the process is the same as described.
Several suggestions are therefore put forward. The design can be simplified by the
implementation of tables for the most common hoop patterns and spacings for current
column dimensions, where the degree of confinement can be read directly. Reference
[3] presents tables of this kind in which the mechanical volumetric ratio of confining
hoops of rectangular cross-sections is evaluated as a function of the cross-section
dimensions, the concrete cover, and the hoop bars diameter, spacing and pattern.
However, for low ductility structures, the whole process should be simplified with a set
of rules similar, even if more conservative, to the ones proposed within EC2. As for the
higher ductility structures, further checking is needed in order to make sure that the
levels of confinement reinforcement computed according to EC8 are really necessary in
terms of the final goals. If these levels are confirmed, it is highly predictable that
designers and promoters will be less than enthusiastic to make use of such structures.
Another aspect introduced by EC8 concerns the range of reinforcement ratios
allowed after the local ductility rules are verified. Both for beams and columns, this
range is very limited independently of the ductility demands. As an example, the
longitudinal reinforcement ratio may, in practice, be limited from around 1% (clause
2.8.1.3(8)P) of the transverse section area to 2% (because of the splicing of bars, usually
done at half the height of the floors). This strongly limits the designers ability to adapt
to changes from the initially predicted action-effects as the calculation using increasingly
sophisticated models proceeds. It will certainly become more common to have to change
the dimensions of the structural elements in the middle of the process.
The minimum cross-section dimensions for columns imposed by the EC8 vary with
the ductility class and tend to aggravate the correspondent values according to EC2.
This is a welcome tendency as it is nowadays a common practice to use very slender
9

11. columns (at least in one of the directions) in seismic regions, with some already proven
bad results. However, it has to be said that these measures will increase the problems of
the compatibility of the structure with the architectural concept. This problem is very
much aggravated in walls, specially if uncoupled, in which the cross-sections resulting
from the application of EC8 concerning boundary elements (clauses 2.11.2.4(2) and (3))
result in extremely anaesthetic elements, that bulge at the ends of the walls. Some of
these rules should be softened in situations in which there is a significant reserve of
resistance, such as when the walls are made of concrete for functional or aesthetic
reasons and not because they are indispensable in terms of seismic design.
4. REGULARITY CLASSIFICATION CRITERIA
According to clause 2.2 of Part 1-2 of EC8, building structures are classified as
regular and non-regular. A distinction is made between regularity in plan and regularity
in elevation. This classification has consequences on the following aspects of seismic
design (Table 1): the structural model (plane or spatial); the method of analysis
(simplified or multi-modal); the value of the behaviour factor.
Table 1 [1] - Consequences of structural regularity on seismic design
Regularity Allowed simplification Behaviour
Plan Elevation Model Analysis factor value
Yes
Yes
No
No
Yes
No
Yes
No
Plane
Plane
Spatial (a)
Spatial
Simplified
Multi-modal
Multi-modal (a)
Multi-modal
Reference
Decreased
Reference
Decreased
(a) under specific circumstances, a plane model and a simplified analysis may be used.
4.1 Regularity in plan
The criteria for regularity in plan are mainly qualitative and consensual. However,
the last clause , 2.2.2(4), states that, under a seismic force distribution correspondent to
the fundamental mode shapes of plane models in both directions of the building applied
with an accidental eccentricity equal to 5% of the floor-dimension perpendicular to the
direction of the seismic action, the maximum displacement in the direction of the
seismic forces must not exceed, at any storey, the average displacement by more than
20%. Several comments can be made [4].
10

12. The first concerns the fact that, in many cases, it is not possible, using only plane
models, to determine with precision the ratio between the maximum and the average
displacement in a given direction under a force distribution eccentric towards the mass
centre. This statement is specially true in buildings whose global behaviour is difficult
to predict, such as dual frame-wall structures. Thus results that, in order to validate the
classification of regular in plan and consequently the use of a plane model, a spatial
model is needed, which makes the whole exercise useless.
y
x
b
a
0.05 a Q
s M
ky
kx
Kp
Figure 6 [5] - Dual frame-wall symmetric buildings
A very simple parametric study of one-floor symmetric buildings with the floor rigid
in its own plan (Fig. 6) proves that, in the great majority of real buildings, it is not
possible to verify the clause stated above. In Fig. 7 the coefficient ξ represents the ratio
between the global effects (translation plus torsion) of the seismic action in both frames
farther from the stiffness centre (in this case, the centre of the building) and the
translation effects in the same frame. ξ has the same meaning as the coefficient δ
defined in clause 3.3.2.4. of part 1-2. Kp is the stiffness of a single wall coinciding with
the stiffness centre and KTy is the building further stiffness in the same direction
(uniformly distributed ky), the same as the seismic forces. It is shown that almost no
building complies with the above requirement, which is only met if ξ < 1,2.
11

13. Figure 7 [5] - ξ for dual frame-wall symmetric buildings
This last conclusion is strengthened by the fact that in the design of dual system
buildings, it is very difficult to avoid small asymmetries when positioning the walls in
plan. Because the contribution of these walls to global stiffness is very significant, these
asymmetries are responsible for eccentricities in the inertia forces and further rotation of
the building around the stiffness centre. Even in dual system symmetric buildings, the
concentration of the walls near the stiffness centre undermines the ratio between the
torsional and the translation stiffness. Under these circumstances, the vibration modes
associated with torsion gain relative importance in the multi-modal analysis because of
the mass accidental eccentricities. In frame systems, its relatively moderate torsion
stiffness allows the imposed accidental eccentricity of the forces to introduce important
rotation movements in the building, with the result that the criterion is also not met.
EC8 allows the use of coefficient δ, to quantify the torsional effects in certain
buildings which are regular in plan. In a building in which the stiffness and mass centres
coincide in every storey, this coefficient’s maximum value is 1,3 for the border elements.
As displacements and action-effects are proportional in elastic analyses, it would be
more coherent if the maximum value allowed for the ratio between maximum and
average displacements were changed to 1,3 instead of 1,2.
Besides these arguments, the authors believe that the decisive factor to choose a
simplified analysis (with a plane model) instead of a multi-modal one (with a spatial
model) should not be the relative value of the torsion effects as compared with the
correspondent translation effects in each direction, but the accuracy with which such
effects can be estimated using the simplified analysis. Therefore, it is suggested that the
range of application of simplified analyses can be widened to include structures in
which global torsion effects are significant, as long as it is possible to estimate with
12

14. some accuracy these effects. The most important task is to identify the parameters that
will allow the distinction to be made without using sophisticated analyses.
A parametric study [2] has been made, in which the parameters identified were the
ratio between the torsional stiffness of the building and its translational stiffness (both
computed using only plane models), tr, and the ratio between the eccentricity of the
stiffness centre from the mass centre and the floor-dimension perpendicular to the
seismic forces, bir. The study was made using multi-storey buildings, rectangular in plan
and regular in elevation. The conclusions for these buildings were that the simplified
analyses (plane model with correction for torsion by means of an approximate
coefficient) may be applied outside very low ranges of the relative torsional stiffness (tr
< 0,20), a non advisable seismic design under any circumstances.
As stated in Table 1, in some cases of structures non-regular in plan, a simplified
analysis is allowed. However, according to Annex A of Part 1-2 of EC8, the range of
structures in which this simplification is accepted does not include any dual frame-wall
buildings, excluding almost all medium to high rise building in seismic areas.
4.2. Regularity in elevation
Most of the criteria concerning regularity in elevation are easy to understand and
apply. The fact that in clause 2.2.3 quantitative limitations, schematically represented in
Fig. 8, have been imposed on setbacks, is a positive factor even though some remarks
must be made concerning its practical use [4].
The limits imposed are independent of the relative importance of the setbacks in plan
(it is necessary to know whether the rules apply if the setback does not cover the whole
width of the building); in this sense, they may be very limitative.
A very popular design with architects is to have a significant setback on the last floor
of the building. If, for this reason, all the action effects have to be increased by 20%
because the building ceases to be regular in elevation, the economic feasibility of this
last floor may be jeopardised. This and other situations (such as the “floor” made up by
the roof of the stair and lift cases) should be referred specifically as exceptions to this
rule, because of its small relative importance in the mass of the building.
Very frequently, there is an important and single setback near the base of the
building for functional reasons. In such situations, the way the rules of clause 2.2.3 are
13

15. written allows for the following interpretation of verification of one of the criterion. The
designer must implement two structural models of the building: one of the real building;
the other of a fictitious building with all storeys equal in plan to the upper floors. In this
last one, the total base shear force is computed. 75% of this force must be resisted in the
first model by the structure within the vertically projected perimeter of the upper stories.
The rule should be re-written in order to facilitate its application.
The situation of underground setbacks is not mentioned. It is tacitly understood that
they do not affect the regularity classification.
L1
L2
L1 L2
-
L1
≤ 0.20
a)
L
H
0.15 H
L3
L4
L3
L 4
+
L
≤ 0.20
(setback occurs above 0.15 H)
b)
c)
L
H
0.15 H
L3 L4
L3 L4
+
L
≤ 0.50
(setback occurs below 0.15 H)
L1
L2
L L2
-
L
≤ 0.30
d)
L
L1 L2
-
L1
≤ 0.10
Figure 8 [1] – Criteria for regularity of setbacks
5. DUCTILITY CLASSES
According to the required energy dissipation capacity, three ductility classes are
considered in EC8 (clause 2.1.3 of part 1-3): low (L), medium (M) and high (H). The
option for a certain ductility class is matched with different criteria regarding material
properties and design criteria, such as evaluation of design action-effects, provision of
14

16. confinement reinforcement, minimum reinforcement ratios and minimum dimensions of
structural elements.
For the highest ductility class, H, these criteria (clause 2.11.1.3(5)) sometimes lead to
design shear forces similar to the ones obtained from an elastic analysis [6], in which
case no advantage is taken of the energy dissipation capacity by hysteretic behaviour.
The rules for detailing of confinement reinforcement are also very stringent, leading to
situations of difficult on site execution that can only be solved with high labour costs.
Requirements regarding minimum dimensions of boundary elements of walls often
collide with architectural requirements. The approximation between the maximum and
minimum reinforcement ratios also creates problems in current design practice as it
limits severely the freedom of the designer, eventually forcing the change of member
dimensions after analysis.
These factors will probably lead to a situation in which ductility class H is hardly used
at all. That is the experience in the authors’ country, in which the present code [7], dated
from 1984, allows for two levels of demand regarding energy dissipation capacity. After
a trial period, the higher ductility level, even though much less stringent and complex than
EC8 requirements for the ductility class H, was almost completely abandoned due to the
economic disadvantages and difficulty of application. It is therefore considered that two
ductility levels are enough, suggesting that ductility class H should be abandoned.
6. OTHER TOPICS
The above discussion focuses on some of the most relevant topics which are likely to
cause problems in the implementation of EC8 but it does not cover exhaustively all
those aspects. A list of other topics worth further thought, some of which are also
susceptible of raising practical problems in current design practice is presented:
• the return period for the earthquake action and the lack of guidance on how to
design for different return periods (clause 4.1 of Part 1-1);
• local verifications for non-structural elements (clause 3.5 of Part 1-2);
• the consideration of the same value of accidental eccentricity e1 for both static and
dynamic analysis (clauses A4(5) of Annex A and 3.2.1 from Part 1-2);
15

17. • the need to account for the vertical component of the acceleration in certain
conditions (for instance, small cantilevers in current buildings) (clause 3.3.5.2(1)
of Part 1-2);
• the non consideration of waffle slab buildings in EC8 Part 1-3;
• the fact that no guidance is given to deal with the existence of architecturally
imposed soft storeys (for instance, by reducing the value of the behaviour factor);
• the non consideration of 2nd
order effects simultaneously with seismic action-
effects (clause 4.2.2(2) of Part 1-2);
• the possibility of choosing to design columns in simple or biaxial bending for
ductility classes “M” and “L” (clauses 2.8.3.2(1) and 2.8.4.2(1) of Part 1-3);
• the need for the alignment of the centre of gravity of columns and beam sections
to (practically) coincide (clause 2.7.1.2.1(3) of Part 1-3);
• the limitation to the maximum diameter of the steel bars at the joints, resulting in
difficult casting and vibrating conditions (clause 2.7.2.2.1(1) of Part 1-3);
• the definition of resisting masonry panels and the respective interference in the
buildings seismic behaviour (clause 2.9 of Part 1-3);
• detailing of beam-column joints (clause 2.10 of Part 1-3);
• sliding shear verification for structural walls (range of application and practical
results) (clause 2.11.2.1.4 of Part 1-3);
• detailing of short coupling beams, namely hoop spacing (clause 2.11.2.2 of Part 1-3).
7. CONCLUSIONS
EC8 is a document that embodies much of the research done in the last two decades
in the field of seismic resistant structures. Some concepts such as capacity design, local
ductility in critical regions and structural regularity have been greatly developed. The
result is a dense, complex document, close to a manual in seismic design.
There has always been a discussion about the scope that the codes should cover.
Some very eminent engineers such as Prof. Roger Lacroix, Honorary President of FIP,
feel that ‘the increased complexity of calculations tends to mislead the designer who is
inclined to rely excessively upon mathematical calculations and to lose the physical and
structural feeling, the most important guide for good design’ [8]. Obviously this opinion
is not shared by the commission that produced EC8.
16

18. Very often the practical application of the theoretically sound rules embodied in EC8
turns out to be a fastidious process, that greatly increases the effort of the structural
designer. The document is also not free from spelling errors, ambiguities, omissions and
hard to understand clauses. There is a clear tendency to control the work of the engineer,
in such aspects as the imposition of the structural model and the method of analysis.
Clearly, EC8 and probably some of the other Eurocodes need to be structured in such
a way as to identify the main principles that the designer must not stir clear off and then,
as comments to guide him in the practical application of these concepts, most of the
clauses from the present version. A revision in which the points of view of the structural
designer, the architect and the building owner are taken into account is also paramount,
in order to soften the present theoretical biased image of the document.
Regardless of these comments, it is obvious that from now on structural designers
have to understand that building design will be done in two stages: the present design,
in which structural elements are dimensioned and detailed; the verification stage, mostly
concerning the critical regions, in which, through an iterative and at the beginning long
process, the local ductility requirements are guaranteed.
8. REFERENCES
[1] Eurocode 8 - Design Provisions for Earthquake Resistant of Structures, Parts 1-1,
1-2 and 1-3, ENV 1998-2, Brussels, 1994.
[2] J. de Brito and M. Lopes, Range of application to current buildings of static
analyses using plane models in terms of its regularity, (in Portuguese) Portuguese
Journal of Structural Engineering, n.º 43, pp. 41-56, Lisbon, 1998.
[3] J. de Brito and A. Gomes, Design tables for confinement hoops of the critical
regions of columns according to Eurocode 8, (in Portuguese) ICIST Report DT
2/96, Instituto Superior Técnico, Lisbon, 1996.
[4] J. de Brito and M. Lopes, Regularity in plan in current buildings versus method of
analysis and structural model, (in Portuguese) Seismic Engineering students manual,
Structural Engineering Masters Course, Instituto Superior Técnico, Lisbon, 1998.
[5] M. Lopes and J. de Brito, Discussion of EC8 criteria for structural regularity in
plan, Proc. 6th
SECED Conference on Seismic Design Practice into the Next
Century, pp. 451-457, Oxford, 1998.
17

19. [6] J. de Brito and A. Gomes, Practical comparative analysis of REBAP and Eurocode
8 applied to reinforced concrete dual systems, (in Portuguese) Portuguese Journal
of Structural Engineering, n.º 42, pp. 25-48, Lisbon, 1997.
[7] Reinforced and Prestressed Concrete Structures Code (REBAP), (in Portuguese),
Lisbon, 1984.
[8] R. Lacroix, Incidence of Codes on concrete bridge economics, FIP notes 1997/4,
pp. 17-19, Lausanne, 1997.
18
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