Effects over the last decades. Many great bridges

Effects of Environmental conditions are a challenging
and tedious task and the designer would encounter extreme problems in the
foundation of bridges. The most crucial factor that may control the design of
bridges over water is environmental conditions rather than ground condition
unlike the design of bridge foundation on land which is govern by ground
condition discarding the environmental factors leads to the collapse of bridges
environmental factors that can influence the
life expectancy of the bridge Therefore, it is considerably significant to understand the
environmental conditions that over bridge design
such as soil factor, calamity factors, land type, light affecting the arena. In
this paper the review of 7 papers is described with their all aspects in the
area of civil engineering.

 

Keywords –DC motor, ATMEL
microcontroller, Metro train, Motor driver IC

 

                                                                         
I.           
INTRODUCTION

 The
fast growth of populations has created new needs for mobility and increased the
demands for constructing efficient bridges. The growth in bridge construction
has been very progressive in many countries around the world over the last
decades. Many great bridges have been built successfully while others has not,
Thus, building on an extensive knowledge to design, plan, construct and manage
efficient bridge construction will contribute to mobility that is safe and
reliable with a minimum impact on the environment. In spite the fact that
bridge construction has experienced positive development trends compared to the
past years.

The interrelation of effectiveness
parameters, geographical areas, time span and disciplines are monitories below
is the stat for the survey in different geographical view of site or in
different geographical arenas.

As it has been mentioned, several
researchers who viewed different sites represented that are involved in the
bridge construction processes. Also there are several effectiveness were
considered by these researchers. It is amazed to see if this has any influence
on the successful bridge construction. On the other hand, in order to draw a
holistic view over that, it is initially important to analytic judgment these
parameters more critically with regard to their geographical differences

 

                                                                       
II.           
PROBLEM
STATEMENT

 

There
are several natural factors which also affects the bridge formation like landscape,
river valleys, soil rigidity and sunlight.

 

A. LANDSCAPE

A landscape is the visible features of an area of land, its landforms and how they
integrate with natural or man-made features, A landscape includes the physical
elements of geophysically defined landforms
such as (ice-capped) mountains,
hills, water bodies such as rivers, lakes, ponds and the sea, living elements of land cover including
indigenous vegetation,
human elements including different forms of land use, buildings and structures, and transitory elements such as lighting and weather conditions. Regional
differences are also very important in considering landscape needs. Irrigation
is often the major concern in terms of management and the expense of repairs
and upgrades. In markets with expensive land, not enough room for trees is an
important consideration.

 

B. SUNLIGHT

Cold weather can affect
construction adversely, hence it is always advisable to take initial and important
precautions to combat these effects. It is advisable to follow the building
codes Perhaps the most critical factor in construction operations carried out
in cold weather is ensuring that mortar and grout get adequate heat for normal
cement hydration. Lower temperatures either completely stop or slow down the
process of cement hydration due to lack of heat, which reduces the masonry’s
bond strength. Frozen masonry units must be melted and dried before implementing
them in use. Measure the unit temperature using a metallic surface contact
thermometer or flat, instant-read thermometer. It is advisable to heat bricks
even when ambient temperatures are above 20 ºF (-6.7 ºC). Preheated brick will
have the same absorption characteristics as that laid at normal temperatures.

 It is important to protect mortar from
freezing temperatures. A frozen mortar mill significantly reduces the
compressive strength (concise strength), the bond strength and also decrease
the water penetration resistance of masonry. Also, mortar with water content
more than six percent of the total volume may be damaged, as the frozen ice may
melt to increase its volume thereby reducing its bond strength.
Consider alteration of mortar constituents and proportions within the possible
range to reduce the impact of cold weather. Also increasing the sand content
can give a stiffer mortar mixture. Using lime content will allow mortar to loss
of water easily.

 

Figure.3. Sunlight

 

C.                 
SOIL RIGIDITY

When soft to firm, clay can
exhibit large settlements under load.  These settlements are likely to
occur slowly due to clay’s poor drainage characteristics.  Pore pressures
within the clay particle spaces move slowly, leading to long-term consolidation
settlement.  Regionally, different clays exhibit different and unique properties.
Swelling clay exists in many areas (particularly throughout the Prairie
Provinces).  This clay can shrink or swell upon changes in moisture content.
This can lead to subsidence or settlement.  Soil heave is also an issue
when it comes to clay, and swelling clay in particular, having the potential to
push the foundation and the structure above upwards.

Sandy
soil has naturally shifting characteristics; drainage through sandy soil
further increases its shifting properties. This poses a clear challenge for any
structures being built on this type of soil. Loose sand can be subject to large
settlements, and these settlements tend to occur quickly due to the
free-draining granular nature of sands.  This can pose foundation
challenges and loose sand requires densification in order to provide sufficient
settlement control and bearing for new structures.

Strength
of stress factor for soil with respect to different materials is represented
graphically below-

*soil-soil

*soil-concrete

*soil-steel

Figure.3. Soil
factor

 

D.                 
RIVER VALLYES

Rock for river valleys is one of
the oldest constructional material known to man, and yet only, till recently
very little was known about its structural behavior. The increasing size of
loads imposed on rock foundations has caused disastrous failures. In the design
of structures to be founded on the rock, it is necessary to recognize that the
foundation rock has definite limitations when used as an engineering material.

The structure
foundation bearings and grinders may not be visible. Bridges span over gaps in
terrain or earth surface ,such as gorges formed due to river valleys and
natural cavity in topography.

Below are some types of river valley pictorial views

  

 

Figure.3. River
valley

 

                                                                                                                                                 
III.           
LITRATURE REVIEW

 

 

 

                                                                                                                                                             
IV.           
CONCLUSION

In case of every wide range construction project,
there are always some environmental impacts on the surrounding of the site This
paper is useful in developing projects & enhancing the construction field which
has a bright future as these factors are being used in countries like UAE, France
& USA. This paper work also helps in increase the number of projects that
cannot be performed successfully. By implementing these useful plan and design
it is possible to construct environment friendly infrastructures, protect
biodiversity and vegetation and also to the proper control of economy, agriculture,
transport and land management. Floods, riverbank erosion, settlement
displacement and char livelihoods problems will be minimized, and make the
island stable. This work will lead to increase in technological trends. Now our
main aim is to implement environmental laws for the successful construction of
structures.

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