It is an simple and very practical method.

This paper introduced the simple synthesis of α -alkyl- β -keto sulfones.

A simpler calculation method is raised.

Design and manufacture of the arch support in the junction arch-lining in arch setting heading;

Finite element analysis of the whole stability of a certain arch centering;

The construction method of concreting layer by layer and segment by segment could reduce the use of steel and save construction cost,when concrete box arch ring was built cast-in-place with aid of arch centering.

On the basis of the project,the paper discusses several details questions about the construction of long span reinforced concrete arch bridge with arch centering casting-in-place,providing some experiences for the similar bridge construction,to guarantee the progress and the quality of project.

With the new arch bridge at Nanxun of Huzhou, Zhejiang as a practical example, the paper outlines the construction processes related to the assembly of steel arch sections for the through tied arch bridge on soft soil foundation, and the forming and the erection of steel arches, etc.

The columns are l ocated at the four corners of the slab with a live load of 5kN /m 2 ,while,with the addition of architectural surfacin g and decoration load,it will be 8kN /m2 .

Combined with practical engineering,the author introduces design of unbraced shuttering from reinforced centering design,shutter-ing and bolt shank,illustrates its installation,and concludes its feasibility,which to make the operation of this technique more economically and reasonably to popularize this technique.