Ability of ferrocement to raise the resistance of reinforced concrete beams subjected to impact load

مقدم أطروحة جامعية

Atiyyah, Abd al-Amir Ubayd

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم هندسة البناء و الإنشاءات

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2000

الملخص الإنجليزي

Structure integrity is the important factor in design of multistory building, this is due to the initiation of progressive collapse caused by some abnormal loading eventuallv results in the collapse of a whole building.

Such abnormal loading is caused by gas or bomb explosive, vehicular and aircraft collision with the building and errors in design and construction.

For the new structure, experience has shown that the overall integrity of structure can be substantially enhanced by main changes in the detailing of the reinforcement. The methods that satisfy the integrity requirement for reducing the abnormal loads for new structures are strengthening the joints used between precast panels by using additional dies system and strengthening of exiting reinforced concrete member, with different techniques which give a great deal to offer an improvement in the performance of the various constructions under their ultimate strength or abnormal loading. Strengthening reinforced concrete beams by a thin layer of ferrocement gives favorable properties such as smaller crack spacing and width, greater toughness which increases their impact load capacity, excellent bond in contact surface, and superfluity of formwork. The purpose of this experimental program is to show the effect of combination of conventional reinforced concrete beam encasement with a thin layer of ferrocement. In this work, the first part of the experimental program covers the effect of some variables that affect the application of ferrocement in strengthening of reinforced concrete beams that are subjected to impact loads.

The effect of number of layers of wire mesh, thickness of ferrocement, shape of encasement, amount, fastening and distribution of skeletal steel; mortar strength and nature of bond between concrete and ferrocement are considered.

In addition two reinforced concrete beams were constructed with low compressive strength to investigate the behavior of ferrocement with more than one type of concrete mix subjected to impact load.

The work also includes testing of quality control specimen. 300 specimens and 1400 laboratory tests were needed to choose the nine parameters, that lead to study fourteen conditions through twenty rectangular reinforced concrete beams with dimension of 150 x 200 x 3000 mm.

For example to study of the nature and effect of contact surface between the reinforced concrete beam and the skin of ferrocement, five micro beams were needed, the first beam with normal contact surface, the second with rough surface.

Grease, polymer bonding agent and epoxy resin bonding agent were used for the other three beams.

Testing thirty-five specimens led to choose the two most suitable conditions to study the full-scale beams according to the engineering requirement and economy. From the load versus number of blows relationship and deflection versus number of the blows relationship, the usefulness of ferrocement encasement to improve the impact load resistance of rectangular reinforced concrete beams was observed.

The reinforced concrete beams encased by ferrocement elements developed an impact resistance, which is up to 8 times that of the bare reinforced concrete beams, and the strength is almost dependent on the detailing of ferrocement composite.

التخصصات الرئيسية

الهندسة المدنية

الموضوعات

• الخواص الميكانيكية

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-306243