It is considered the foundation is the structural element which transfers
loads applied in all load conditions to soil incorporation, thus achieving
stability and resistance and landings allowed economic and testing the
appropriate requirements.
Thus this research will conduct a comprehensive study of cracks and
landings and trends that take place in the old facilities, and to identify the
reasons for their occurrence.
This research study the impact of additions to improve
limestone mortar properties to become comparable to hydraulic
lime which is used in other countries, by using additions relative
to that were used in the old mortar, also used modern additions
like fiber glass to limit unwanted contraction in the use of
limestone mortar, , especially in arid environments.
This research deals with analytical study of exterior Beam-Column
connections behavior under seismic load.
Tow parameters were considered: axial load on the column and
confinement of joint region with stirrups.
Ansys program was used to analytica
l study of three types of exterior
Beam-Column connections under cyclic load.
The results were shown a good agreement with general behavior of
three types.
The analytical results indicate that the tow parameters will improve
the behavior of the connections delay cracking at joint core and
increasing connection stiffness in rotation and displacement with
decreasing shear value at joint.
this study aimed to evaluate and compare enamel
cracks caused by removing of the adhesive remnant post debonding
of the fixed orthodontic appliance.
If it is not cracked then it is not working. This statement is the actual result of difference
between tension strength of concrete and tension strength of steel in concrete structures
elements that are economically designed.
In spite of that, eng
ineers rarely use this statement to explain cracks in buildings, but
sometimes they use it to calm down the owner of some cracked building. That's why we should
define acceptable cracks and their degrees.
Cracks in concrete and reinforced concrete structures are a bad sign, although some of
these cracks have no negative effect on the utilization of the structure.
Reasons of cracks are various and different, some of them might occur in different types
of cracking while others may lead to a single type of crack.
Cracks formation in concrete varies due to the different factors causing them, which also
may be structural or related to the utilization of building.
It is not easy to put a useful list for probable reasons of cracking as cracks have many
shapes and any one of them might increase the danger of another one or even exceeds it. To
explain the relationship between these types, we proposed the cracking tree, which may help
the designer to take into consideration the probable reasons for cracking.
The main specification of cracks is that its three nodes define the three periods in the life
of a structure: design, construction and service. These are also divided into lists including
reasons causing cracking and their effects on each other.
Cracking tree branches into tension roots, taking into consideration that the first branches
determine the physical properties of cracks (width, depth, length,…). Then these branches
take their way throughout the three phases,(restriction of movement is the most important
branch). When these branches stop growing, they can tell the severity of cracking, in respect
to durability and beauty. This definitely still needs accurate study and repair.
This research aims to study the direct reasons of cracking, factors that increase cracks,
and types of cracking growing in structural members (Columns, Beams, Plates,..). Add to that
the procedures needed to prevent or stop cracks growing. We also offer an attempt to point the
best methods and materials to be used for restoration.
Our Paper is a laboratory modeling research to evaluate the efficiency of finite element model in emulation the behavior of R.C. beams with shear deficiencies (ultimate load, mechanism of cracking and failure, load-deflection behavior) strengthened w
ith GFRP strips.
We tested nine R.C. beams 200x30x16 cm in three groups, the first consists of three R.C.beams for comparing, the second consists of three strengthened R.C. beams with two sides vertical GFRP strips, and the third also consists of three strengthened R.C. beams with two sides inclined (45°) GFRP strips.
We modeled these beams by advanced finite element program Ansys10, and we get results agreed with our laboratory study.
The mixed use of steel bars and carbon rods in concrete beams can offer beams with different behaviour from that of steel reinforcement only. This paper studies the case of reinforcing concrete beams with two layers of bars, and the main parameters
investigated are the proportion and the distribution of carbon rods in the cross-section. Four groups containing 12 beams are tested, and each is reinforced with 4 bars located in two layers. The first group includes three control beams reinforced with steel bars, while the second includes three beams reinforced with carbon bars. Each of the third and fourth groups includes three beams reinforced with two steel bars and two carbon bars, whereas in the third group, steel bars are located above carbon ones, but in the fourth group, steel bars are located under carbon ones. Concrete beams reinforced with carbon rods in the second group exhibit a higher load carrying capacity and deflections, compared with other beams. However, the beams in the third and fourth groups have approximately the same load carrying capacity and the same behaviour up to the load level equal to 75% of their load carrying capacity. But after that, the beams in the fourth group become more deformed, compared with those of the third group.
