và BTCT toàn
khối,
ABSTRACT
Determination of
seismic loads acting on building structures according to TCXDVN 375: 2006 with
a simplified procedure (pp.3-7)
Dr. nguyen dai Minh, Eng. nguyen hoang Anh
This paper presents a simplified procedure for
determining seismic loads acting on building structures according to TCXDVN
375: 2006: Design of seismic resistant building structures. The procedure is
applicable to calculation and design of building structures in seismic prone
regions. When applying this procedure to design, possible mistakes caused by
engineers can be avoided.
Unbonded
post-tensioned prestressed concrete beams subjected to uniformly distributed
loads (pp.8-11)
A/Prof. Dr. Nguyen tien chuong
Unbonded tendons in prestressed concrete
structures can freely move along its axis. Due to this feature, the analysis of
unbonded prestressed concrete structures is a very complicated problem.
Experimental methods are applied to Design standards to solve this problem.
In this paper, the author presents results of a
study on the behaviour of Unbonded post-tensioned prestressed concrete beams
subjected to uniformly distributed loads. The main result of the study is a
system of equations that can be used to determine the flexural strength of the
beam.
Adjustment
of natural frequencies of multi-storey building with HDR embedded (pp.12-16)
MEng. tran
tuan long
Structural vibtation
strongly and affects to the design and performans of the construction. One
solution reduce the vibration of the structure under seismic-incluced load, is
to use a device called HDR (High damping rubber bearing) to isolate the
structure from its base.
This article estimates
the influence of the structural and the HDR device parameters to the natural
frequencies of HDR – embedded structure of multi-storey building.
Oscillation of inverse
pendulum equiped with Tunned Mass Dampers (pp.17-23)
A/Prof.
Dr. khong doan dien, MEng. nguyen
duy chinh
In reality, there are many structures that can
be modeled in the inverse-pendulum form such as buildings, antenna tower,
drilling rig e.g. Of the development of science and technology, these
structures are getting to become higher and larger in size. Increasing the
structural sizes will lead to the complicatedly dynamic responses and
vibrations unfortunately that affect the ordinarily working condition of the
structures. Therefore, studying and decreasing these oscillations are recently
very hot problems. Paper represents the way to establish the mechanical and
mathematical models in order to determine the vertical and horizontal
oscillations of structures with inverse-pendulum form that are installed the
absorber. The results obtaining from the investigating of the inverse-pendulum
will be applied to study, analyze, calculate, and design optimally to find the
parameters of damper that reduces the detrimental oscillations of
inverse-pendulum-formed structures.
Towards Better
Evaluation of Design Wind Speed of Vietnam (pp.24-35)
MEng. Le Truong
Giang, Prof Yukio Tamura, A/Prof. Masahiro Matsui
The aim of this study is to seek an answer for
the appropriate procedure to evaluate design wind speeds of Vietnam. Surface wind data of 108 meteorological
stations obtained from the National
Hydro-Meteorology Data Center
and other sources were used in this study.
Finally, an appropriate treatment is proposed to deal with extreme winds
based on available wind records. In addition, weaknesses or uncertainties in
assessment of design wind speeds also are discussed.
Studying for producing self-compacting
concrete of grade 200 (pp.36-42)
Dr. Tran
Ba Viet, MEng. Le Minh Son
Self-compacting concrete is the type of concrete that can
self-leveling owing to its self-weignt and filling up all area of the form,
including the area of dense reinforcement.
This paper presents a study for producing self-compacting concrete
of grade 200 using materials available in Vietnam. The studying results have
shown the limit boundary condition of compotion used for self-compacting
concrete of grade 200, the influence of the hot and humid climate condition on
the the development of compressive strength, the shrinkage, workability of the
produced self-compacting concrete.
Cleaning steel rust with steel rust
conversion agent of B-05 (pp. 43-46)
Dr. Pham
Van khoan, Eng. tran Nam
Steel rust is the phenomenon that is widely seen on building
structures in the Vietnam
hot and humid climate conditions. When
bare steel is exposed to the external humid environment, yelow rust can appear
on the steel surface. If the exposure time is longer, the steel scale will be
formated, significantly affecting the quality of steel. For reinforeced
concrete structures, steel rust will reduce the boding forec between
reinforcement and concrete, increasing the rist of being corroded during the
using process. Therefore, steel rust must be cleaned prior to placing concrete.
At present, there are many ways to clean the steel rust. In this
paper, the authors introduce a part of the research results on the conversion
of steel rust caused by B-05 – one of the converters used to clean steel rust.
The role of
polypropylene fiber on reducing plastic shrinkage of concrete hardening in the
conditions of Hot and Humid Climate of Vietnam (pp.47-52)
Dr. Nguyen
Tien Binh, Dr. Tran Ba Viet
Plastic shrinkage of concrete hardening in the
conditions of Hot and Humid Climate of Vietnam is rather high. It often causes
strong cracks in the surface of concrete structures, so reduces their quality.
That’s why limiting plastic shrinkage is one of the important tasks of
Vietnamese experts in solving problems relating to the increase of concrete
quality. In this paper, an experimental investigation on the effectiveness of
using polypropylene fiber at the ratios of 0.1% and 0.3% by volume for limiting
plastic shrinkage of concrete with different monitoring models is presented.
Some matters on permissible tolerances
when constructing concrete and reinforced concede structures (pp.53-55)
Eng. tran manh nhat
In this paper, the author presents, analyzes some stipulations,
which are, according to the author, not
reasonable in the TCXDVN 4453: 1995: Monolithic concrete and reinforced
concrete structures – Standard of construction and acceptance. The author also recommends
some changes so that this standard can suit the technical capacity available at
present. The recommendations by the author should be carefully considered and
analyzed from many aspects when deciding to review and amend the standard
accordingly.
