1.In reinforced concrete elements, the steel bars embedded in concrete provide the :
tensile strength/ductility
2. ......... refers to the determination of the particle-size distribution for aggregates.
Grading
3. Using the slump test on fresh concretes, the following characteristic is determined:
workability/consistency
4. The ...................... developed by the section must balance the applied loads for static equilibrium.
resultant forces
5. To increase the fresh concrete workability of the concretes in order to maintain a low water-cement
ratio, the next admixtures are used................
water reducing admixtures, superplasticizers
6. In the reinforced concrete beams, the concrete failure ............. the rotation that may take place at a
section in bending.
limits
7. To obtain concretes with high compressive strengths. it is necessary to decrease ..........
water-cement ratio
8. For permanent and transient design situations, the partial safety factor for concrete has the value.........
gama c=1.5 (γc=1.5)
9. The interaction between reinforced bars and surrounding hardened concrete is called .........
bond (contact force, adherence)
10. The primary purpose of ........ is to establish the distribution of internal forces and moments, and to
identify the critical design conditions at all sections.
structural analysis
11. The cement component with the highest compressive strength after hydration is................
alite c3s
12. The design of members with shear reinforcement is based on ............
analogous truss
13. The theory of bending of reinforced concrete assumes that the concrete will crack in the region of
tensile strains and then, after cracking, all the tension is carried by ......
the reinforcement
14. The phenomenon of increasing the reactivity when the materials size decreases are known
as....................
surface area effect
15. The ...... of the flange of a T-section may be calculated by considering the flange as a system of
compressive struts combined with ties in the form of tensile reinforcement.
resistive capacity
16. The magnitude of the ......... is required for the deflection and cracking investigation of a reinforced
concrete member.
tensile strength
17. If the water-cement ratio is lower than the concrete compressive strength is ........
higher
18. The characteristic compressive strength fck derives from strength test by the criterion that 5% of all
possible strength measurements for the specified concrete may be expected to fall ................... the value
fck.
below
19. Extra water increases the workability but .......
reduces compressive strength
20. lf the reinforcing bars .................... is not adequate, the bars will slip within the concrete.
anchorage length
21. Shrinkage in concrete is ...................... to load application.
reduction of its volume independently
22. When determining the ultimate moment resistance of reinforced concrete cross-sections, the following
assumption is made: .......
sectiunea este considerata in stadiu complet plastic, in stadiul ultim al unei sectiuni betonul
intins se considera fisurat si se considera doar armatura intinsa si betonul comprimat
23. The term "high strength concrete" refers to the concretes with the characteristic compressive strength
fck ......
50<=Fck<=120
24. The term ......... refes to the value of actions to be used when a limit state is under the influence of
different actions.
combination of actions (In Eurocode the term "combination of actions" is
specifically used for the definition of the magnitude of actions to be use when
a limit state is under the influence of different actions
25. The phenomenon that appears at the concrete strengthening and consists in the reducing of its
volume, independently by the load’s application, is called .............
shrinkage
26. Shrinkage has the beneficial efect of strengthening ........................ between the concrete and the
steel reinforcement.
the bond
27. The following relation: Ecc(inf,t0)=Y(inf,t0)*(sigma(c)/Ec0)* indicates that the creep deformation
depends by ..................
time
28. The reinforced concrete members should be ...... so that the concrete can be well compacted around
the reinforcement.
VIBRATED/designed
29. The steel reinforcements characteristics that define their ductility behaviour are ......
large strains and yielding before they fail
30. The ... is limited to a value depending on the surface characteristics of the reinforcement,tensile
strength of the concrete and confinement of surrounding concrete.
bonding of reinforcement bars to the concrete
31. The characteristic strengths of materials, corresponding to the 5% fractile are those strengths values
of the tests results..........
below which less than 5% will fail
32. The theory of bending of reinforced concrete assumes that plane sections of a structural
member................ after straining.
remain plane
33. The strengths of materials upon which design is based, below which results are unlikely to fall are
called ......
design strengths
34. A low water/cement ratio will ....... drying shrinkage.
decrease
35. The limit slates corresponding to the conditions beyond which specified service requirements
(deformations, deflections, vibrations, cracking’s of the concrete that affect durability) for a structure or
structural member are no longer met are called .........
serviceability limit states SLS
36. The ..................... in bonded reinforcement, whether in tension or in compression, is the same as that
in the surrounding concrete.
strain
37. In a reinforced concrete beam, a large quantity of steel would allow the steel to ....... at the time of
crushing of the concrete, causing a brittle or sudden mode of failure.
remain elastic
38. The................ reinforcement should be able to resist the additional tensile force caused by shear.
transversal
39. The limit states, associated with collapse, loss of equilibrium of the whole structure ,failure by
excessive deformation, rupture or loss of stability, are called ......
ultimate limit states ULS
40. The effects of torsion and shear may be superimposed, assuming the same value for the ..................
strut inclination 0
41. At the ultimate limit state, the maximum compressive strain in the concrete reaches the value .............
0.0035
42. The ................ of a member subiected to torsion and shear is limited by the capacity of the concrete
struts.
resistance or maximum resistance
43. At ..........., it is important that member sections in flexure should be ductile and that failure should
occur with the gradual yielding of the tension steel and not by a sudden catastrophic compression failure
of the concrete.
ultimate limit state(ULS)
44. The length necessary for developing the required tensile force in an anchorage or lap is calculated on
the basis of a ....................
Lbd=a1*a2*a3*a4*a5*Lb,rgd>=Lb.min
45. How many work stages correspond to a reinforced concrete beam subjected to bending?
3 work stages
46. The spacing of bars shall be such that the concrete can be placed and compacted to ....
develop adequate bond
47. If the loads were removed during the plastic range, then ........
the plastic deformation would remain
48. ln sections where bars are positioned in separate horizontal layers, the bars in each layer should be
located...........
vertically above each other
49. ....... are used to modify the properties of the concrete to make it better serve its intended use or for
better economy.
admixtures
50. At the work stage I of a reinforced concrete beam subjected to bending, the following relationships are
valid:
σc<fcd
σct<fct
σs<<fyd
M<Mf
51. At the work stage II, in the crack’s sections of a reinforced concrete beam subjected to bending, the
following relationships are valid:
σc<fcd
σct=fct
σs<<fyd
52. Lapped bars may be allowed ...... within the lap length.
to touch one another
53. At the work stage III, the following relationships are valid:
εc=εcu1 εs>εsc
σc=fcd σs=fyd
54. The ............... shall be sufficient to prevent bond failure.
ultimate bond strength sau anchorage length
55. In a normal-reinforced concrete beam section, the failure will occur when .......
the steel is in the plastic range
56. Thermal stresses and strains may be controlled by the correct positioning of ....................... in the
structure.
movement or expansion joints
57. Reinforcing bars shall be so anchored that ................... are safely transmitted to the concrete.
cohesion btw bars and concrete, stresses (friction)
58. The usual reinforcing ratio for a singly reinforced rectangular .section in bending varies between:
0.3-0.4%<p%<1.5-2.5%
59. When beams exceed........... in depth. side-face reinforcements should be provided.
750mm
60. For a singly reinforced rectangular section in bending, the design relation of resultant compression
volume is:
stress*aria of aftion=lambda*nu*fcd*b
σ*A=λ*η*fcd*b
61. Yielding of the reinforcement enables the formation of..........
plastic hinge
62. Concrete and steel exhibit........... after being subjected to high temperatures.
brittle failure strength loss(softening of steel)
63. The design of basic required anchorage length in a straight bar assumes a ...........
ultimate anchorage bond stress
64. The minimum spacing of reinforcement, to permit concrete flow around depends by the reinforcement
diameter and by ................
aggregate size
65. Reinforcement will retain about.................... of its normal strength after reaching about 550 C.
50%
66. The coefficients of thermal expansion of steel and concrete are ...............
of order 10 at power -6
67. In the following relation: As1=ωlim*b*d*(fcd/fyd)+As2, the notation As1 represents :
cross sectional area of reinforcement at yielding
68. The additional torsional longitudinal steel area may be provided by increasing the size of bars or by
..............
increasing number of bars
69. For equilibrium in double reinforced concrete section, the bending moment MEd must be balanced
by..................
the moment of resistance of the section
70. A large quantity of steel would allow the steel ............... at the time of concrete crushing.
to remain elastic
71. If the reinforcements steel strain : fyd/Es<εs<εud then the steel ......
the steel is in the yielding zone
72. If the reinforcements steel strain:
εs=εcu3*[(d-x)/x]<fyd/Es then
the steel is in the elastic zone
73. If the reinforcements steel strain: εs > εud, then ............
the steel failure appears before the concrete crushing
74. The height of the compression zone for a double reinforced rectangular section is obtained with the
relation:
x={(As1-As2)*fyd}/λ*η*fcd*b
75. It for a T section is accomplished the condition: x <=hf , then the section is computed as:
singly reinforced flanged section T SECTION IS DESIGNED AS A EQUIV RECT SECTION HXB
76. For a singly reinforced flanged section, the following relation:
resist of flange without web
77.
For a double reinforced flanged section, the following relation:
represents:
the capacity in flexure of the area of the web in compression
78. The minimum reinforcement ratio is the lowest relative amount of steel permitted to the prevent ......
brittle failure
79.
Design shear resistance of the member, without shear reinforcement
80. The calculated amount of ................... must be provided in addition to the bending and shear
reinforcement.
torsional reinforcement
81. Under loads, the bending of a singly reinforced rectangular section will induce .........
a resultant tensile force in steel and a resultant compressive force in concrete
82.
the tension steel yields, and the compression steel is in the elastic range
83. The ........................... of links and shear reinforcement is realized by means of bends and hooks.
anchorage
84. If the condition: VEd,Red<=VRd,C is accomplished, then......
we need shear reinforcement
85. The ................ to which a bar is bent shall be such as to avoid bending cracks in the bar.
angle
86. The relation of tangential stress of a reinforced concrete beam with rectangular cross-section, for
variable section height on the beam length, is the following .......
Jourawski's formula
87.
design shear resistance for member with stirrups as vertical shear reinforcement
88.
the additional tensile force, in the longitudinal reinforcement due to shear force Ved
89. In a section of a reinforced concrete beam ................... in the concrete acts through the centroid of
the effective area of concrete in compression.
resultant compressive force?
90. The ............... of concrete is controlled by the proportioning of cement , coarse and fine aggregates,
water, and various admixtures.
class or strength
91. The following relation:
indicates that the basic required anchorage length
depends by:
size of bar ; design bond strength
92. The total torsional moment provided by one closed link is given by .................. due to each leg of the
link about the centerline of the section.
asw/s de T
93. Rough-textured aggregates require ...... to produce workable concrete than smooth, rounded compact
aggregates
more water
94. In the relation of the effective modulus of elasticity of the concrete:
the creep coefficient equal to the ratio of the creep strain to initial elastic strain
95. The .........................to ensure adequate bond should not be less than the bar diameter, or equivalent
bar diameter for bundled bars.
min cover
96. The torsional shear stress, TETA(t,i) , in the wall i of the equivalent section, is expressed by the
following relation:
Ted/2AtTef,i ?
97.
transverse reinforcement for torsion
98. Analysis of section subjected to ...... can be done replacing the real element with a virtual spatial
truss.
torsion
99. .............. are time-dependent deformations.
creep shrinkage
100. Additional .............. may be obtained by transverse welded bars.
shear +torsion resistance
101. The reinforcements bends and hooks ................... to compression anchorages.
do not contribute
102. Tensile forces are transmitted from one bar to another by lapping of bars, welding’s or ..............
hooks or mechanical devices
103. In the concrete mixture, extra water increases .............., but reduces strength.
workability
104. ............... is required in the lap zone to resist transverse tension forces.
transverse reinforcement
105. In an under-reinforced concrete beam section, the failure will occur when......
the steel failure appears before the concrete crushing
106. For bent bars, the basic anchorage length should be measured along ............. of the bar.
horizontal part up or down depends
107. ........... generally, increases its strength with age.
concrete
108. Beams sections containing less reinforcement than As,min should be considered as........
under reinforced or weak
109. .......is the continuous deformation of a member under sustained load at unit stresses within the
accepted elastic range.
creep
110. For a double reinforced flanged section, the following relation: MRd3 = As2 * fyd * (d - d2) ,
represents .......
the capacity in flexure of the reinforcement in compression
111. After cracking the reinforcements in the form of ............... and longitudinal bars will carry the forces
from increasing torsional moment.
closed links
112. The value recommended value of As,max for beams is ........
As,max=0.04*Ac
113. The tension strength of concrete affects the extent and size of......... in reinforced concrete elements.
cracking
114. The shear reinforcement should form an angle of between ................... to the axis of the structural
element.
21.4-45
115. The ................... should be closed and anchored by means of laps or hooked ends and should form
an angle of 90 with the axis of the structural element.
longitudinal reinforcement
116. The following relation : x = (As * fyd) / (λ*η*b*fcd) represents ...............
the height in compression zone
117. For a rectangular reinforced concrete section, when: μlim < ( MEd)/b*(d^2)*fcd < 0.50 then ..........
compression reinforcement is required
118. The cross-sectional area of tension or compression reinforcement should not exceed As,max ..........
0.04 A sectiunii
119. The anchorage length lbd of the longitudinal reinforcements is obtained with the following relation:
Lbd=a1*a2*a3*a4*a5*Lb,rgd>=Lb.min
120. The cracks due torsion will form ........... the member.
a spiral around the beam
121. ........... in flexure is important when considering cracking and deflection of beams.
yielding of bars
122. The provision of reinforcements in the compressive zone of a flexural member helps to restrain the
deflections due to ...................
negative bending moment
123. The distance z between the resulting compression force in concrete and the tensile force in
reinforcements is called.......
lever arm
124. After the ................, mild steel becomes a plastic material, and the strain increases rapidly up to the
ultimate value.
yield point
125. Which are the unknowns when a beam subjected to flexure is checked to the ultimate limit state of
resistance?
real resistance moment of a beam Mrd
126. ..............and durability affect the choice of the grade of concrete.
exposure, compressive strength needed(loads on the structure),
127. For a reinforced concrete beam subjected to bending is necessary an amount of tension steel Asl,b
to provide the neutral axis: xb = [(εcu2) / (εcu2 +εsl)] * d for the balanced strain condition.
Choosing an effective amount of steel Asl > Asl,b ,then the beam behaviour will be:
the failure of the beam will be sudden and the beam
would exhibit little deformation to warn of imminent failure
128. The resistance moment of a singly reinforced rectangular section in bending is obtained with the
following relation:
Mrd=As,eff*fyd*z
129. The shapes of reinforcing bars in a member must be fully dimensioned and listed in a ................. of
the reinforcement.
(Reinforcement detail table- technical drawing book) tabloul de armatura
130. ............ should be provided at all sections to resist the envelope of the acting tensile force.
longitudinal reinforcement
131. The following relation : x = [(As1 * As2) * fyd] / (λ*η*b*fcd) represents ...........
the distance from the maximum compressed zone to the neutral axis
132. Tensile strength is a ................ variable property than compressive strength.
more
133. Torsional moments produce ..............
shear stresses
134. The .................... provided at supports with little or no end fixity assumed in design, should bs at
least 1/4 of the area of steel provided in the span.
reinforcement
135. ....................... requires that the structure must be able to withstand, with an adequate factor of
safety against collapse, the loads for which it is designed.
Ultimate limit state (ULS)
136. The concrete at ............................ of a member is generally less compacted and tends to have a
greater water content.
at the upper surface?
137. If the following relation: VRd,s <= VRd,max is accomplished, then ........
stirrups are needed ceva de genul
138. ................. on a structure are divided into three types: dead, variable and accidental.
loads
139. For a reinforced concrete beam subjected to bending is necessary an amount of tension steel to
provide the neutral axis for the balanced strain condition. Choosing an effective amount of steel lower
than this, the beam behaviour will be......
plastic, steel failure is before concrete crushing under reinforced, high deformation without
concrete crushing
140. From the design to bending in normal section results .................
necessary area of reinforcement
141. It is necessary to know the bending moments, torsional moments, shearing force
and ........... in each member to design a structure.
axial force
142. At the work stage II, between the cracks of a reinforced concrete beam subjected to bending, the
following relationships are true :
sigma c <fcd sigma s<<<fyd
143. In an over-reinforced concrete beam section, the failure occurs when ...............
steel is in elastic stage, sudden failure
144. For members ........... ΔFtd may be estimated by shifting the moment curve a distance at a1 =d.
in tension
145. A reinforced concrete structure should be analyzed for each of ...................... conditions, which
produce the maximum stresses at any particular section.
bending shear torsion axial
146. For the analysis of the stresses on a cross-section of a reinforced concrete element must be
considered the equilibrium of the forces in the concreteand steel, and also the .,..........,.... across the
cross-section.
neutral axis si daca nu este a varianta compatibility of the strains
147. The calculus relations of the principal tension and compression stresses
(sigma 1 and sigma2) are ......
sigma 1=fyd sigma 2=fcd
148. If the loads on a reinforced concrete beam were removed during the plastic range, then
........................would remain
plastic permanent deformation
149. ............... is necessary to transfer the forces from one bar to another.
overlapping, welding, plate hooks/mechanical devices
150. Analysis of sections subjected to torsional moments can be done replacing the real element with
...................
a virtual spatial truss?
151. The bending moment diagrams for each load’s arrangements and the corresponding shear force
diagrams are combined to give the bending moment and shear force ......
critical/dangerous sections
152. The shear in a reinforced concrete beam without shear reinforcement is carried by a combination of
following components: concrete in the compression zone, aggregate interlock across flexural cracks and
...................
doweling action of tensile reinforcement
153. The relation: ρw = (Asw) / (s * bw *sinα) is the design expression of .....................
reinforcement ratio for shear reinforcement
154. For equilibrium, ....................... must be balanced by the moment of resistance of the section.
Med effective design moment
155. Lower-strength concrete has ................... ductility than higher-strength concrete.
higher
156. In order to reduce the cross-section size of a beam, to control the long-term deflection or when
alternate bending moments act ............. must be used.
compression reinforcements have to be used
157. In a reinforced concrete beam, a section may be considered virtually ............. until the steel yields
and then plastic until the concrete fails at compression.
elastic
158. The effective flange width for a T or L beam is: beff = bw +beff,1 +beff,2, where beff,i = 0.20 * bi
+0.10 *l0 <= 0.20 * l0. In the last relation l0 represents:
active length of the flange
159. If the cracks appear at an opposite angle on the lateral faces of a rectangular reinforced concrete
beam, then these cracks are caused by:
torsion
160. If the cracks appear in the bottom part of a precast reinforced concrete beam, simply supported on
supports, in the middle zone of me span, before the beam is loaded, then these cracks are caused by:
bending moment due to self-weight
Additional questions :