MASANGKAY EXAM W/NOTES
1. around elevator
2. over reinforced
- undereinforced: lesser evil
- steel will yield first, then concrete will crack; code
calls it RUNNING TIME
- balanced section: rc beam sections in which the
tension steel also reaches yield strain
simultaneously as the concrete reaches the failure
strain in bending
a. under reinforced: lesser capacity; PROVIDES
MORE WARNING prior to failure
WHAT IS THE MEANING OF KG*M/S2? Newton
(N)
5. retaining wall
- "resis lateral displacement of soil" aka prevents
erosion
- understand gravity wall, piling wall, cantilever, and
anchored wall
- gravity: tapered, enough to withstand forces
- piling: manipis pero nakatanim sa lupas
- cantilever: meron paa to the left and under the
soil, weight of soil will be enough to prevent sliding
- anchored: there is an anchor towards the soil
- "the failure in under reinforced beam section is
due to the concrete reaching its ultimate failure
strain of 0.0035 before the steel reaches its failure
strain which is much higher 0.20 to 0.25."
6. diaphragm
- can we consider slab as diaphragm? yes if slab
includes the bracing systems
- bridge diaphragm: provide a stiffening effect to
deck slab
- dual systems: economic alternative to momentresisting frames (SOLID); combination of momentresisting and concrete
b. over reinforced beam sections
- failure strain in concrete is reached earlier than
yield strain of steel
- failure is all of a sudden, not recommended
- considered critical compared to under-reinforced
7. soft story
- lateral STIFFness is less than 70% of the stiffness
of story above
- solution: rc wall, steel frames
concrete ultimate failure strain: 0.0035
steel failure strain: 0.20 to 0.25
3. essential facilities (chapter 1 of NSCP)
- READ OCCUPANCY TABLE of structural code
4. gravity load
- temporary and imposed loads
- e.g. permanent loads (wall, floor) imposed load
(human, furniture)
- soil bearing capacity
weight of concrete: 1500-2500 KG/M3
normal weight: 2400 kg/m3 OR 23544 N/m3 OR
23.6 kN/m3
weight of steel:7750 kg/m3 to 8050 kg/m3
normal weight: 7850 kg/m3 OR 77 kN/m3 OR
77008.5 N/m3 OR 490 lb/ft3
**To get weight in N/m3, just multiply weight with
9.81 ,/s2
8. weak story
- It is one in which the story strength is less than
80% of the story above.
- retrofitting is the only solution
- storey shear:
- storey drift: lateral movement
9. P delta effect
- secondary effect on shears (therefore may
primary)
10. concrete
- artificial stone, properly proportioned cement,
aggregates etc.
11. admixture
- admixture or additives
- inert materials: considered aggregates
- more water, the weaker the concrete
- too little, not workable
12. masonry
- not only concrete, but also concrete blocks
- mostly general, includes plaster
20. hold longitudinal bars in place
- stirrups resist vertical and diagonal tensions as
well
- column that bends: buckling
- beam that bends: deflection
13. lintel
- supporting opening of windows and doors above
- girder: primary beam
- girt:a small beam that you can see in double
walling
- tie beam: not intended to carry load, to prevent
internal buckling
21. use of concrete vibrator
- honeycomb in concrete can be limited by this
-vibrator: 12k - 17k vibrations per minute
- tightly packed particules will result in stronger
concrete
14. elasticity
- stretch without failure
- malleability: shaped into something else
- creep: slow and progressive deformation of a
material with time at constant stress; timedependent strain
15. crippling
- sharp bending or buckling
16. crushing and buckling
- usual failure
- effective height of column divided by least
dimension of column; less than 12, short column,
more than 12 long column
17. creep
- long term exposure to high levels of stress
18. bundled bars
- in contact as A UNIT
- minimum: 2 bars
- maximum: 4 bars
- if clear distance between main bars of column is >
150mm or 6 inches, you need to add stiffener or
CROSS TIE
19. slab
- span is much greater than thickness; useful
surface
- one way slab or two way slab
- one way slab: span considered is the shorter span
- two way slab: refer to short direction first, top bar
is along the long direction ALWAYS to minimize
deflection
22. fault lines
- at least 5 meters from fault line
23. columns
- for TIES (tied column)
24. planted
- concentrated load acting on the beam
- not aligned to bottom columns
25. pre-tensioning
- pre-tensioning and post tensioning = prestressed
concrete
26. moment frame
- frames in which elements resist forces
predominantly shear and axial
27. punching shear failure
- failure of a base when hole is striked through; ex:
lumusot yung slab pababa
- flexure stress: happens to columns and beams,
but it means bending
28. bond stress
- prevents relative movement between bar and
surorunding concrete
- deformed bars; we provide anchorages 90, 280,
or 135 bend to increase bond strength
29. stirrup
- reinforcement to resist shear;
- two functions: resists lateral and tortional stresses
in a beam + hold main bars in place
- tied columns: called 'tie'
30. jacking force
- TEMPORARY force to introduce tension for prestressing
- if no word na temporary, pre-stressing force can
be considered
31. structural concrete
- concrete for structural purposes (KEYWORD)
- concrete: artificial stone, very strong in
compression
32. settlement
- DOWNWARD vertical ground movement, changes
in/ increased vertical stresses due to expansive
property of soil (e.g. when it gets wet)
- gradual movement of earth when heavily loaded
33. permeability
- ability of soil to allow water to flow through it
- can be seepage or capillary
- seepage: absorption along horizontal direction
- capillary: rise vertically; water in the water table
tries to wet soil above it, until wetness goes up
completely
- soil test required for 2 stories
- you are required to embank 200-300 mm of layer
for filling (cut and fill) but dpwh requires 200mm (8
inches); layers of 200 mm, you must achieve 9095% density. if not, settlement may occur
- cement (1/7 or 14/3%) : sand (2/7 or 28.6%) :
gravel (4/7 or 57.1%)
37. load-bearing wall
- the wall that resists vertical loads
- biggest load it resists is the load parallel to it
38. contraction joint
- manmade groove in a concrete structure to create
a weakened plane and regulate location of
cracking; way to control cracking
- ground slab thickness is 200 mm, depth of groove
is 200/4
- X/4 is depth of groove (x=slab thickness)
*construction joint
- pour concrete monolithically; but if you need to
stop, stop at L/3. dugtungan ng old and new:
construction joint
- sometimes, you provide dowel
*isolation/expansion joints
- insertion of material that does not bond to
concrete, between to concrete sections
39. development length
- length of embedded reinforcement for design
strength at critical section (kung saan pwede
maghiwalay)
34. workability (and consistency)
- function of slump test
- 4 inches is the maximum
- 100mm (top) 200mm (bottom) openings, 300mm
height
- VOL OF CONCRETE = VOLUME OF SLUMP
CONE
*dowels
- smooth bar or deformed bar, pang dugtong lang
naman
vol of concrete - H/3 (A1 + A2 + sqr.A1A2)
A1 = area of small opening
A2 = area of big opening
41. sheathing
- material encasing prestressing reinforcement
- prevents reinforcement from blending with
concrete
- protects from corrosion
35. retarder
- DELAYS onset of hardening
- setting of concrete = hardening
36. aggregates
- more than 75% of concrete
- class A mix: 1:2:4 (cubic feet for all)
40. post-tensioning
- method of pre-stressing where tensons are
tensioned AFTER concrete has hardened
42. allowable stress
- working stress: actual stress developed in a
material
- maximum safe stress
43. thermal stress
- stress induced from change in temperature
44. spiral reinforcement
- wound reinforcement (in main bar) in form of
cylindrical helix
- beams: STIRRUPS
- tied column: LATERAL TIES 4-16 bars, minimum
250mm per side
- round column: SPIRALS 6-16 bars
- ** which is STRONGER? spirals
45. inflection point
- point in the beam where no moment is developed
= zero moment
- point in the elastic diagram where the curvature
changes (pinaghiwalay ang concave upward and
downward)
46. dike
- long wall or embankment built to prevent flooding
- if specifically SALTwater: seawall is the answer
- dam: used to impound water for water supply
47. chevron
- bracing that terminates at a single point within
clear beam span
- can be letter V or inverted, or siagonal line
48. pedestal
- upright compression member (COLUMN) with
ratio of clear height to average least lateral
dimension not exceeding 3
- column na pandak; usually tapered
- if tapered: get the average
- COLUMN: generally an 'upright compression
member'
49. isolation joint (expansion)
- separation of existing concrete slab from new
concrete slab
- separates two slabs
50. welding
- used to fasted components of built-up member
(e.g. plate girder, steel to steel members) to make
connections with FUSION (chemical combination
between metals)
-welded and bolted connection (trying to provide a
little flexibility)
- minimum size of weld: 5mm
- FILLET WELD; study symbols
a. butt joint
b. lap joint
c. t-joint
d. corner joint
e. edge joint
51. natural
- knot in wppds or timbers
- 2 types of drying: air, kiln
52. 6db
- minimum inside bend diameter for deformed bar
10mm - 25 mm
- P4-163 NSCP 2015
- required by code to provide extension length (90
deg 12db, 180 deg greater of 4db and 65)
53. 75 mm
- talking about clear distance
- maximum spacing of spirals
- aggrgate, gravel: 9.5mm-20mm
54. 0.9
- strength reduction factor for flexure
55. 12mm
- minimum size of slab main reinforcement
- temperature bar
56. m < 0.5
- ratio of width to length for one way slab (two
supporting beams)
57. m >= 0.5
- ratio of width to length (
58. 4-16mm dia.
- minimum reinforcement for TIED column (and
beams)
- never use 12 for columns or it will be substandard
- slabs: 12mm minimum (10 is substandard)
- spiral: 6-16mm
59. 6-16mm
- minimum reinforcement for spirral column
60. A36
- ASTM steel with yield stress of 36000 psi
- fc concrete yield stress
- 1 ksi = 1000 psi
61. 100mm
- minimum thickness of ONE way slab
62. 20mm
- slabs not exposed to weather or in contact with
ground must have this minimum clear cover
- doesn't matter which type of slab
- ex: 42mm diameter bar for the slab; so slab must
be superslab. 40mm concrete cover
- MEMORIZE TABLE specified concrete cover for
non-prestressed members and pretressed
63. 3/8 inch
- coarse aggregates must be larger than this
- coarse aggregates = gravel
- minimum of 9.5 (3/8 inch is 9.375)
64. 20.685 mpA
- strength of concrete at 28th day is 3000 psi. value
is same as
- 1 MPa = 145.038 psi
- 1 psi = 0.006895 MPa
65. 60 ksi
- closest answer is 40ksi
- grade 60 steel yield stress of 275.8 MPa
- IMPORTANT: GRADE 40 276 MPa, GRADE 60
414 MPa
66. 0.75
- shear and torsion
67. general purpose
- ASTM Type I cement
- portland cement inventor: joseph aspdin in
portland, england
- fastest curing (type iii): 3 days
- ordinary: 7 days
- normal curing: 28 days
Type I = normal
Type II = moderate sulfate resistance
Type III = high early strength
Type IV = low heat hydration
Type V = high sulfate resistance
68. 25 mm (perfect)
- diameter of a no.8 deformed bar
- to determine diameter of bar given its number:
BAR NUMBER / 8 * 25
- NEVER USE 8 FOR STRUCTURAL, minimum is
10mm
- Philippine Standard Steel Bars (pi)d^2/4
- check hour 5:32 for computation hahaha
** Curing - retention of moisture
7850 KG/M3 steel
69. 75mm
- minimum concrete cover for concrete in contact
with ground, para hindi kalawangin mga bakal
70. 300mm
- lap splices for uncoated deformed bar must not be
less than larger of 48db and ____
- now, must not be less than 40db
71. 36mm
- maximum diameter of bars that can be bundled
- larger than 36mm should not be bundled
72. 25mm
- minimum clear spacing between parallel bars
73. 4
- maximum number of reinforcement for bundled
bars
- might be asked to determine equivalent diameter
- equivalent diameter = DIAMETER WHEN
BUNDLED, just one big circle (equivalent bar)
- 𝛑�d^2/4 * 4 = 𝛑�de^2 / 4
74. 1/8 wL^2
- maximum moment of simply supported beam L
meters long, carrying uniformly distributed load of w
(N/m)
- draw shear and moment diagram ;__;
- W = L(m) * W (N/m) = WL, N
- web reinforcement, shear reinforcement =
STIRRUPS
75. ld
- minimum length of Class A splice
- Class A: 1ld
- Class B 1.3ld
- Class C 1.7ld
- ld shall not be less than 300mm
76. stud welding
- welding to fuse metal studs by heat of electric arc
- STUD is equipped with ceramic ferrule
77. at L/3
- where one can stop pouring concrete if
monolothic pouring is impossible
- for girder x beam, joints must be located at
LEAST TWO BEAM WIDTHS away from beamgirder intersections
- loop of reinforcing bars enclosing reinforcement in
tied columns
84. wall
- used to enclose or separate spaces and
sometimes serve as a structural member
85. 1.5
- seismic importance factor 1p of hazardous
facilities and essential facilities
86. aggregate
- inert material mixed with hydraulic cement and
water to produce concrete
- AKA granular material
- shape: best is round and texture smooth
- aggregate classification: size, specific gravity,
availability, shape, texture
78. composite
- 2 or more materials that are combined together
- composite girder: steel-beam composite or rc slab
- built-up section: same materials combined
together
87. 25 mm
- spirally reinforced concrete column, clear spacing
shall not be larger than 75 mm and not less than __
79. own weight and wind load
- forces a curtain wall resists
89. 0.888
- weight of 1 meter no. 4 bar deformed bar
W=7850 kg/m3 * volume
Volume = cross sectional area * length
colume = pi dsquare/4 * 1 m
W = 0.888
80. stirrups
- resist vertical and diagonal tensions in a beam
and hold main rebars in place
- AKA web reinforcement, shear reinforcement
81. long column(slender column)
- will mostly fail due to buckling
- slenderness ratio kl/r
- RATIOS short, <32; intermediate, 31-120; long,
>120
82. effective depth
- distance measured from extreme compression
fiber to centroid of tension reinforcement
- more likely it's a beam
- more bars at bottom than top, subjected to tension
- more bars on top than bottom, might be
cantilevered beam
83. ties
88. post-tensioning
90. stress
- intensity of force per unit area
- may tend to change the size of body
- force developed / cross sectional area
91. end anchorage
- length of reinforcement BEYOND POINT OF
ZERO STRESS
- 180 degree bend, 90, etc
92. basic wind speed
- 3 second gust speed at 10 meters above ground
93. storey drift
- displacement of one level relative to level below
- storey drift ratio: storey drift / storey height
94. 800mm
- splices of deformed bars shall be staggered in this
amount
- "splices shall be staggered at least 750mm" mas
malayo, mas safe
- minimum separation of NOT LESS THAN 40 bar
diameters
95. crosstie
- continuous reinforcing bar having a SEISMIC
HOOK
- dont need crosstie if distance between bars is 25150mm
96. L/10
- not less than 100mm and L/10
97. marquee
- permanent roofed structure attached to and
supported by the building, projecting over public
RROW
98.
- minimum concrete cover for non-prestressed
beams and columns NOT exposed to weather /
earth
99. 12mm
- minimum tie or hoop diameter for bundled bars
100. 10mm
- for cast-in-place construction, spirals shall not be
less than this amount for 16mm-32mm
longitundinal bars
- larger than 32mm, you have to use 12mm na
101. 8db
- go backt to Standard Hook Geometry for
Deformed Bars
PLAN READING
102. main rebars
103. lateral ties
104. 3 meters (from ground line to bottom)
105. combined footing (two column footings are
combined, can be trapezoidal; if 3 or more,
grid/continuous footing na)
106. tied columns
107. 4
108. 6 (main bars, no ties included!)
109. 8
110. tied
111. 4-16mm (min. for tied columns)
112. one-way slab
one way slab if:
- supported by 2 beams on two opposite sides
- supported by beam on all sides, RATIO of longer
span to shorter span is > 2 OR if short direction to
long direction < 0.5
113. two-way slab
114. two-way slab
115. one-way slab
116. one-way slab
117. two-way slab
118. L/24
S-1, one and continuous L/24
119. P/180
S-3, you cant choose ABC (L/20,24,28) they are for
one-way slab
120. 100mm
121. 20mm
122. temperature bars (since one way slab)
123. 12mm (S-6 two way slab, both top and bottom
are main bars)
124. linear meter
125. flat slab (only columns)
126. flexural stress
127. rupture(nabiyak na, lumubog pa)
128. sublimation (pwede ka mabuhay)
129. rupture
130. earthquake
hypocenter - ilalim ng lupa
epicenter - ibabaw ng lupa
131. fault line
132. 6m
133. 8m
134. 20m
135. 6m
136. 7.21m
137. 7.5m
138. 5.5m
139. 5.5m
140. 7.5m
141. 3.7m
142. web reinforcement
143. main bars
144. 40mm
145. 75mm
146. 12mm
147. 36mm
148. A. 5wL^4
149. zero (may support, walang deflection)
150. midspan, because of symmetry
151. main bars
152. AOTA
153. 4 inches
154. 16 mm
155. 400mm
156. 2000mm
157. rectangular footing
158. 75mm
159. 6-16mm both ways
160. tied columns
161. 600x600
162. 15-16mm, one way
163. 12
164. 1.65
165. 150mm
166. 75mm
167. 9.80m
168. steel (angle bar)
169. 1087.5mm
170. 75x75mm
171. gutter
172. 16mm
173. 12mm
174. 3
175. slab, one-way slab (designed per linear meter)
176. cantilevered slab
177. isolation gap
178. 122-16mm
179. 600mm
180. 5
181. 16mm
182. 500mm
183. isolation gap
184. 75mm
185. 30
186. 24m
187. lateral support
188. angles
189. L50x50x6mm
190. symmetrical (cambering is intentional curving)
191. camber (to minimize deflection)
192. modified mercalli scale (effect of magnitude is
INTENSITY)
193. creep
194. rigid frames
195. 200GPa (modulus of elasticity of struc. steel)
196. 7/8
197. fillet welding (FUSION)
198. mean roof height
199. 1.5 importance factor
200. open building
201. exposure D
exposure categories:
- A: highly built-up areas
- B: roughest terrain (urban, suburban, wooded
areas)
- C: open terrain
- D: smoothest, most severe windload, up to 2km
from sea
REVIEW rebar size markings