"requested to reinforce" is correct and usable in written English.
You can use it when you want to emphasize that an action was requested of someone. For example, "The commander requested to reinforce the troops at the front lines."
A few months back, we presented an official request to reinforce and strengthen our bridges.
Therefore von Bock had before the invasion requested to be reinforced in this effort by another Army Corps.
Through this contrivance of association the club's fans took it upon themselves to begin singing the popular music hall tune before home games, sometimes reinforced by the presence of a house band requested to play the refrain by Charlie Paynter.
They are requested to come back to the hospital accompanied by a relative, if possible, to foster a supportive home environment and reinforce the importance of treatment adherence.
Others requested to be transferred.
Donations requested to Breast Cancer.
The army has temporarily banned any broadcast or publication "detrimental to national security"; asked 10 politically affiliated satellite and cable TV stations to cease broadcasts; prevented protesters from marching outside of their protest areas; and told police to reinforce the military, if requested.
Under the new policy, the United States is also no longer requesting port calls in Hong Kong, requests that the Pentagon had previously made to reinforce the territory's unique status.
To reinforce their case, they also requested asylum.
After the conference, Milner requested that the British government send additional troops to reinforce the British garrison in Southern Africa; they began arriving in August and September.
