Civil engineering is a branch of engineering that deals with infrastructure development to support human life from the past to the present. Civil engineering is the second oldest profession in the world. Some examples of civil engineering infrastructure buildings include residential houses, tall buildings, offshore platforms, electric towers, dams, irrigation canals, ports, bridges, roads, railroads and others. As can be seen from the examples mentioned, civil engineering science has considerable scope. Therefore, in general the field of civil engineering is usually subdivided into several sub-areas of expertise, among others:
Structural areas of expertise
Field of transportation expertise
Field of geotechnical expertise
Field of water resources expertise
The field of construction engineering management expertise
The field of building systems engineering expertise (building system engineering)
The field of civil informatics expertise
Below, we will try to describe the various fields of expertise in civil engineering:
The field of structural expertise usually relates to the strength, security and stability of an infrastructure or building. So the task of a structural expert is to plan and calculate the main frames of an infrastructure building so that the building is strong, safe, stable and not forgetting economically. Some of the main points discussed in the structural field include reinforced concrete planning, prestressed concrete planning, steel structure planning, structural analysis, structural planning due to earthquake loads and also wind, building planning, bridge planning and others. In the field of structure is also discussed about the behavior of materials commonly used for infrastructure buildings such as concrete, steel and wood. It is the responsibility of a structural expert to know which materials are suitable for use in an infrastructure development project.
The field of transportation expertise usually deals with issues related to the planning, planning, and operation and management of transportation facilities such as roads, railways, airports, ports and others. The sciences that need to be studied usually include the determination of the geometry of the road, the planning of the pavement, the transportation system and also on the management and management of the means of transportation.
The field of geotechnical expertise is the field that relates to the foundation and the ground that supports the foundation. The foundation is part of the lower building which is designed to accept the load from the structure above it. Included in this area is a soil investigation to determine the type, carrying capacity and depth of hard or rock layers of an area.
The field of water resources expertise is the field related to water, distribution, control and problems. Major issues of interest in this area include hydraulics (surface and underground), fluid mechanics, irrigation and reservoirs or dams.
The field of construction engineering management expertise is a field related to the implementation of a construction or construction project such as job scheduling, project organization, construction cost calculation, etc. to ensure a project is completed on time and economically.
The area of building systems engineering expertise is the field related to energy efficiency in commercial and industrial buildings and renewable energy use. This field is usually discussed issues of energy management, building intelligence, building processing, renewable energy and also the modeling of the movement of energy in the building.
The field of civil informatics expertise is a new field that combines civilian fields with informatics. Because of this modern era, a lot of civil engineering fields that are closely related to the field of informatics, especially in the field of numerical calculations. For example, the usual finite element method applications are found for structural analysis, soil carrying capacity analysis, hydraulics, fluid mechanics and others. Prior to the establishment of this field, usually the use of numerical calculations is done by civil engineers. But with the increasing complexity of problems encountered in the field of civil engineering such as trying to analyze the behavior of new materials that have never been used before. This requires a fairly complex numerical calculation technique that requires the assistance of an imformatics expert. Matters discussed in this field include numerical calculation techniques such as finite element method, finite difference method, and finite volume method. Also discussed is the programming method to create programs as mentioned above and the use of CAD (Computer Aided Design) to support and facilitate the implementation of a project.
WHAT IS CONCRETE CONCRETE
With the advancement of construction technology in the current era and the higher the use of concrete in the construction world, prestressed concrete is a great solution to meet the needs of concrete because prestressed concrete has many advantages along with a brief description of prestressed concrete.
A. CONCRETE CONCRETE DEFINITIONS
The definition of prestressed concrete according to some rules is as follows:
A. According to PBI - 1971
The prestressed concrete is a reinforced concrete that has produced internal pressure with value and division such that the pressure of the concrete can be neutralized to the desired level.
b. According to the Draft Consensus Concrete Guidelines 1998
Prestressed concrete is a reinforced concrete that has been given a deep voltage to reduce potential tensile stresses in concrete due to loading of work.
c. According to ACI
Prestressed concrete is a concrete that undergoes a large internal stress and distribution in such a way that it can offset to some extent the voltage that occurs due to external loads.
B. PRINCIPLES AND HOW TO CONCRETE CONCRETE CONCRETE
To provide a concentric style on prestressed concrete can be done in two ways:
A. Pre-tensioned Concrete Concrete (pratarik), is a construction in which the tendon is stretched with the help of a helper before the hardened concrete and concentric strength is maintained until the concrete is hard enough.
b. Post-tension Preconding Concrete (post-tension), is a construction where after the concrete is hard enough, then give a concentric style by pulling the wire of the tendon.
This prestressed steel prestressing method before the concrete is cast, is therefore called the pretension method. The principles of this Pratarik briefly are as follows:
Stage 1: Prepare a full formwork with a hole for the tendon channel mounted curved into the point beam field, after which the concrete is cast (Figure A).
Stage 2: After the concrete is thrown and can already withstand its own weight, the tendon or prestressed cable is inserted into the Tendong Hole (tendon channel), then drawn to obtain a prestressed style. The prestressed method is to bind one armature, then the other end of the armature is drawn (taken from one side). but some are drawn on both sides kemudiang simultaneously. Once grown kemudiang done grouting on the hole (Figure B).
Stage 3: After being crossed, the concrete beam becomes depressed, so the concentric force has been moved to the concrete. Because the tendon is mounted curved, consequently the tendon's concentric power provides a uniform load of upside tendencies, consequently the shape of the beam is bent upward (figure C).
To facilitate the transportation from factory to site, prestressed concrete is usually made with a post-voltage system applied segmentally (beams are divided into sections, for example divided into lengths of 1 to 3 m).
D. BREAKING STAGE
Unlike conventional concrete, prestressed concrete undergoes several stages of loading. At each stage of loading shall be checked for the conditions of press fiber and tensile fibers of each cross section. At that stage, a valid voltage permits varies according to the condition of the concrete and the tendon. There are two stages of loading on prestressed concrete, ie transfer and service.
- The transfer stage is the stage when the concrete has started to dry and the prestressed cable pulling is done. At this point it is usually the only dead load structure that functions, ie the weight of its own structure plus the workload of workers and tools. At this time the live load does not work so minimum working time, while the labor force is maximum because there is no loss of prestress force.
- Service conditions are conditions when prestressed concrete is used as a structural component. This condition is achieved after all lost prestressing styles are considered. At this time the outside load is at maximum condition while the prestress strength approaches the minimum price.
C. MATERIAL BETON PRATEGANG
- Concrete is the result of mixing some materials in the form of cement, water and aggregate. with a weight ratio of 44% crude aggregate mixture, 31% fine aggregate, 18% cement, and water 7%. after 28 days the concrete will reach the ideal strength of the so-called strong compressive characteristics. Strong compressive characteristics are voltages that have exceeded 95% of the uniaxial compressive strength measurements taken from standard suppression tests, ie with a 15x15 cm cube, or a cylinder with a diameter of 15 cm and a height of 30 cm. The concrete used for prestressed concrete is a concrete that has a high compressive strength with a minimum f'c value of 30 MPa.
- Steel: steel material commonly used in the manufacture of prestressed concrete is as follows K
• PC Wire, usually used for prestressed steel on prestressed concrete with a pre-pull system.
• Strand PC, commonly used for prestressing steel for prestressed concrete with post-retract system.
• PC BAR, usually used for prestressed steel in prestressed concrete with a pre-pull system.
• Regular reinforcement, which is reinforcement that can be used for conventional concrete such as plain iron and screw iron
D. ADVANTAGES OF CONCRETE CONCRETE
Prestressed concrete has several advantages over conventional concrete, such as:
- Advantages in terms of technical:
• Avoid open cracks in the area of attraction, so that prestressed concrete will be more resistant to corrosion.
• Waterproof, good for projects close to the water.
• Because of the formation of the opponent due to the prewang force before the plan load works, then the final deflection after the plan load works, will be smaller than the ordinary reinforced concrete.
• Efficient because the dimensions of the cross-section of the structure will be smaller or slender, since the entire cross-section is effectively used.
• The amount of steel use is much less than the amount of weight of the reinforcing iron in conventional concrete construction.
• Resistance to shear and resistance to torsion increases.
these technical advantages will affect the cost of producing prestressed concrete itself, and in terms of economical prestressed concrete also has several advantages such as:
• The volume of concrete used for the production of prestressed concrete is less
• The amount of steel / iron used for the production of low prestressed concrete.
• Prestressed concrete will be more advantageous if made in large quantities
• Prestressed concrete barely requires maintenance cost, is more durable because, it can make longer-span beams.
• Using prestressed concrete can save the construction time.
A few posts this time may be useful and can add insight.
Source: PBI 1971, ACI, and Consensus Concrete Guidelines 1998